KACTICAmHANDBOOKSi 


LIBRARY 

OF  THE 

UNIVERSITY  OF  CALIFORNIA. 

GIFT  OF  THE 

STATE  VITICULTURAL  COMMISSION. 


Deceived,  January,  i8g6. 
Accession  No.b/t/2-tf  ..       Class  No. 


THEORETICAL  AND   PRACTICAL 

AMMONIA  REFRIGERATION. 

A    WORK    OF    REFERENCE    FOR    ENGINEERS 

And  others  Employed  in  the  Management  of  Ice  and  Refrigeration 
Machinery. 

BY 

ILTYD   I.  REDWOOD, 

ASSOC.    M.    AM.    SOC.    OF     M.    E.  :       M.    SOC     CHEMICAL    INDUSTRY, 
ENGLAND. 

WITH    25    PAGES    OF    TABLES. 


UHI\ 


NEW  YOKE: 
SPON  &  CHAMBERLAIN,  12  CORTLANDT  STREET. 

LONDON : 
E.  &  F.  N.  SPON,  125  STRAND. 

1895. 


Copyrighted,    1894. 
Copyrighted,    1895. 


Printed  by  Henry  I.  Cain,  35  and  37  Vesey  Street, 
New  York,  U.S.A. 


PREFACE. 


THERE  are  many  engineers  and  others 
interested  in  refrigerating  machinery  who 
have  felt  the  want  of  a  book  of  reference 
that  will  enable  them  to  determine,  with 
sufficient  accuracy  for  all  practical  pur- 
poses, what  work  their  machines  are  doing 
without  resorting  to  laborious  calculations ; 
therefore  a  number  of  tables  have  been  pre- 
pared to  meet  this  want,  and  a  short  treatise 
on  the  Theory  and  Practice  of  Refrigeration 
incorporated  therewith. 

The  tables,  which  have  been  calculated 
as  accurately  as  possible,  and  have  been 
checked  by  a  gentleman  of  considerable 
"expert"  experience,  cover  a  sufficiently 
wide  range  of  temperatures  and  pressures 
to  meet  all  ordinary,  and  a  good  many 
extraordinary,  requirements. 

ILTYD  I.  REDWOOD, 

BROOKLYN,  February,  1895. 


CO 


PAGE 

INTRODUCTORY  REMARKS i 

CHArTER    I. 

BRITISH  THERMAL  UNIT         .         .        .        .        .  3 

MECHANICAL  EQUIVALENT  OF  A  UNIT  OF  HEAT     .  4 

SPECIFIC  HEAT        .......  4 

EFFECT  OF  TEMPERATURE  AND  PRESSURE  ON  SPE- 
CIFIC HEAT 6 

EFFECT  OF  PRESSURE   ON   SPECIFIC  HEAT   OF  AM- 
MONIA GAS 7 

SPECIFIC  HEAT  OF  AIR  \vrni  CONSTANT  PRESSURE  7 

SPECIFIC  HEAT  OF  AIR  WITH  CONSTANT  VOLUME  .  9 

LATENT  HEAT 10 

LATENT  HEAT  OF  LIQUEFACTION       .         .         .         .10 

LATENT  HEAT  OF  VAPORIZATION  .        .        .        .  11 

LATENT  HEAT  OF  WATER 12 

ABSOLUTE  PRESSURE 13 

ABSOLUTE  TEMPERATURE 13 

ABSOLUTE  ZERO 16 

EFFECT  OF  PRESSURES  ON  VOLUME  OF  GASES.  16 


ii.  Contents. 

CHAPTER   II. 

TAGE 

THEORY  OF  REFRIGERATION  .....          18 
FREEZING  BY  COMPRESSED  AIR  .        .         ...        .19 

FREEZING  BY  AMMONIA 21 

CHARACTERISTICS  OF  AMMONIA .22 

EXPLOSIVENESS 23 

TENDENCY  OF  THE  GAS  TO  RISE       .        .        .        .     24 

SOLUBILITY  IN  WATER   ......         24 

ACTION  ON  COPPER    .......    25 

26°  BEAUME  AMMONIA 25 

ANHYDROUS  AMMONIA 25 


CHAPTER    ITT. 

GENERAL  ARRANGEMENT  .....  26 
DESCRIPTION  OF  THE  PLANT  .  .  .  .  .27 
CONSTRUCTION  DETAILS — THE  COMPRESSOR  .  30 
STUFFING-BOXES.  .  .  .  .  .  .  .32 

SPECIAL  LUBRICATION 34 

OIL  FOR  LUBRICATION 35 

CLEARANCE  SPACE,  ETC.         .....         35 

SUCTION  AND  DISCHARGE  VALVES     ...          .     36 

EFFECT  OF  EXCESSIVE  VALVE-LIFT  .  .  .'  37 
REGULATION  OF  VALVE-LIFT  -  ....  37 


CHAPTER    IV. 

THE  SEPARATOR      .        .  3'! 

THE  CONDENSER 42 

CONDENSER-WORM 42 

RECEIVER "       .                .  43 


PAGE 

REFRIGERATOR  OR  BRINE  TANK    ....  44 

SIZE  OF  PIPE  AND  AREA  OF  COOLING  SURFACE        .  45 

EXPANSION  VALVES 46 

WORKING   DETAILS.— CHARGING  THE   PLANT  WITH 

AMMONIA       . 47 

CHAPTER   V. 

AMMONIA  TO  BE  GRADUALLY  CHARGED         .        .  49 
JACKET-WATER  FOR  COMPRESSOR      .        .        .        .52 

JACKET-WATER  FOR  SEPARATOR    ....  53 

CONDENSING  WATER 53 

LESSENING  THE  COST  FOR  CONDENSING  WATER  .  54 

QUANTITY  OF  CONDENSING  WATER  NECESSARY        .  56 

Loss  DUE  TO  HEATING  OF  CONDENSED  AMMONIA,  56 

Loss  DUE 58 

SUPERHEATING  AMMONIA  GAS    .....  58 


CHAPTER   VI. 

EXCESS  CONDENSING  PRESSURE  ....  59 
CAUSE  OF  VARIATION  IN  EXCESS  PRESSURES  .  .  60 
OTHER  CONDITIONS  THAT  AFFECT  EXCESS  PRESSURE,  62 
USE  OF  CONDENSING  PRESSURE  IN  DETERMINING 

Loss  OF  AMMONIA  BY  LEAKAGE     .        .        ,63 
COOLING  DIRECTLY  BY  AMMONIA      .        .        .        .65 

BRINE 66 

FREEZING  POINT  OF  BRINE 68 

EFFECT  OF  COMPOSITION  ON  FREEZING  POINT  .  68 
EFFECT  OF  STRENGTH  ON  FREEZING  POINT  .  .  69 
SUITABLENESS  OF  THE  BRINE  .  .  .  .  .  70 
MAKING  BRINE  .  .  .  .  .  »  .  ,  .71 


iv.  Contents. 

CHAPTER   VII. 

PAGE 

SPECIFIC  HEAT  OF  BRINE 73 

REGULATION  OF  BRINE  TEMPERATURE      .        .        -73 
INDIRECT  EFFECT  OF  CONDENSING  WATER  ON  BRINE 
TEMPERATURE 77 

CHAPTER  VIII. 

DIRECTIONS  FOR  DETERMINING  REFRIGERATING  EF- 
FICIENCY         78 

EQUIVALENT  OF  A  TON  OF  ICE     ....         79 
COMPRESSOR   MEASUREMENT    OF  AMMONIA    CIRCU- 
LATED     79 

Loss  IN  WELL-JACKETED  COMPRESSORS  .  .  80 
Loss  IN  DOUBLE-ACTING  COMPRESSORS  .  .  .80 
DISTRIBUTION  OF  MERCURY  WELLS  .  .  .  81 
EXAMINATION  OF  WORKING  PARTS  .  .  .  .86 
NUMBER  OF  READINGS  TO  BE  TAKEN  ...  86 

CHAPTER   IX. 

DURATION  OF  TEST 87 

INDICATOR  DIAGRAMS 87 

AMMONIA  FIGURES.— EFFECTUAL  DISPLACEMENT      .     97 

VOLUME  OF  GAS 97 

AMMONIA  CIRCULATED   PER  TWENTY-FOUR  HOURS,    98 

REFRIGERATING  EFFICIENCY 98 

BRINE  FIGURES. — GALLONS  CIRCULATED       .        .         99 

POUNDS  CIRCULATED 100 

DEGREES  COOLED 100 

TOTAL  DEGREES  EXTRACTED  .  100 


Contents.  v. 

CHAPTER   X. 

PAGE 

Loss  DUE  TO  HEATING  OF  LIQUID  AMMONIA      .        102 
Loss  DUE  TO  HEATING  OF  AMMONIA  GAS       .         .  103 

CHAPTER   XL 

CALCULATION    OF   THE    MAXIMUM   CAPACITY   OF  A 

MACHINE 106 

PREPARATION  OF  ANHYDROUS  AMMONIA       .        .  107 

CONSTRUCTION  OF  APPARATUS  .        .        .        .  .  108 

CONDENSER-WORM IOQ 

WHY  STILL  is  WORKED  UNDER  PRESSURE        .  .no 

BEST  TEST  FOR  AMMONIA in 

WATER  FROM  SEPARATORS 101 

LIME  FOR  DEHYDRATOR in 

YIELD  OF  ANHYDROUS  FROM  26°  AMMONIA  .  112 


INDEX 


139 


LIST  OF  ILLUSTRATIONS. 

j 


F.g. 

Page 

I. 

Specific  Heat  with  Constant    P 

ressure   Determi- 

nation         .... 

.      8 

2. 

Absolute  Zero  Determination  . 

14 

3- 

Ammonia  Plant     . 

.    28 

4- 

<«              « 

29 

5- 

Discharge  Valve    . 

.          .          .          .     36 

6. 

Suction            " 

•         36 

7- 

Separator       .... 

.     40 

8. 

Expansion  Valve 

.  46,  47 

9- 

Mercury  Well 

.    82 

10. 

f      .         .         .      .. 

.         .         .         84 

11. 

Indicator  Diagram 

.    88 

12. 

"                  " 

.        .        .        89 

13- 

"                  "                . 

.    90 

14. 

"                  " 

91 

'5- 

Anhydrous  Ammonia  Distilling 

Apparatus    .          -US 

TABLES. 

Table  Page 
I.     Volume  of  Ammonia  Gas  at  High  Temperatures,    51 
II.    Yield,  etc.,  of  Anhydrous  Ammonia  from  Am- 
monia Solutions 113 

III.  Boiling  Point,  Latent  Heat,  etc.,  of  Anhydrous 

Ammonia    , 116,  117 

IV.  Temperature  to  which  Ammonia  Gas   is  raised 

by  Compression  ....  n8toi22 

V.  Volume  of  One  Pound  of  Ammonia  Gas  at 

Various  Pressures  and  Temperatures,  122  to  130 
VI.  Volume  of  One  Pound  of  Ammonia  Gas  at 

Various  Pressures  and  Temperatures,    131  to  138 


UHI7BRSITY 


AMMONIA 
REFRIGERATION 


INTRODUCTORY  REMARKS. 

THE  ammonia  "compression"  types  of 
freezing  machines  are  now  coming  so  gener- 
ally into  use  in  large  factories  and  manufac- 
turing establishments  where  natural  ice  was 
formerly  employed,  that  they  are  of  necessity 
placed  directly  or  indirectly  under  the  super- 
vision of  men  who,  owing  to  the  comparative 
newness  of  the  subject  of  ammonia  refrigera- 
tion in  relation  to  the  manufactures,  can  not 
be  expected  to  be  thoroughly  conversant  with 
their  theoretical  and  practical  working. 

In  a  great  many  instances  engineers  who 
have  charge  of  these  machines  only  run 
them  by  rule-of-thumb  methods,  and  know- 


2  Introductory  Remarks. 

ing  nothing  about  the  why  and  the  wherefore 
are,  in  the  event  of  the  conditions  being 
changed,  unable  to  reason  out  what  will  re- 
sult from  the  changed  conditions,  and  what 
other  changes  ought  to  be  made  to  counter- 
balance them. 

It  is  therefore  with  a  view  to  giving  those 
connected  with  the  running  of  ammonia  re- 
frigerating plants  a  more  intelligent  idea  of 
what  they  are  doing — thereby  tending  to 
make  their  work  interesting  instead  of  labo- 
rious— that  this  Book  has  been  written. 


BEFORE  dealing  with  ammonia  refrigera- 
tion it  is  necessary  that  the  different  heat 
terms,  etc.,  that  are  used  in  regard  to  this 
subject  should  be  thoroughly  understood, 
and  they  will  therefore  be  explained  forth- 
with. 

The  terms  with  which  we  have  principally 
to  deal  are  : 

(1)  British  Thermal  Unit. 

(2)  Mechanical  Equivalent  of  a  Unit  of  Heat. 

(3)  Specific  Heat. 

(4)  Latent  Heat. 

(5)  Absolute  Pressure. 

(6)  Absolute  Temperature. 

BRITISH  THERMAL  UNIT. 

A  British  thermal  unit  is  the  standard  unit 
of  heat  in  this  country,  and  represents  the 
amount  of  heat  necessary  to  raise  the  tem- 
perature of  one  pound  weight  of  water  one 


4  Theoretical  and  Practical 

degree  Fahrenheit — the  temperature  of  the 
water  being  32°;  on  the  other  hand,  it  is 
the  amount  of  heat  given  up  by  one  pound 
of  water  in  cooling  one  degree  Fahrenheit 
(i.  e.,  from  33°  down  to  32°). 

MECHANICAL  EQUIVALENT  OF  A  UNIT  OF 
HEAT. 

Joule  found,  by  means  of  a  suitably  con- 
structed agitator  placed  in  water  and  actuated 
by  a  falling  weight,  that  the  amount  of  fric- 
tion caused  by  a  weight  of  I  Ib.  falling  a  dis- 
tance of  772  feet,  or  a  weight  of  772  Ibs. 
falling  a  distance  of  i  foot,  was  sufficient  to 
heat  i  Ib.  of  water  i°  Fahr.  Therefore,  the 
production  of  one  British  thermal  unit  of 
heat  is  equivalent  to  raising  a  weight  of  i  Ib. 
772  feet,  or  772  Ibs.  I  foot,  and  consequently 
the  mechanical  equivalent  of  a  unit  of  heat  is 
772  foot-pounds. 

SPECIFIC  HEA-T. 

Specific  heat  is  the  number  of  British  ther- 
mal units  required  to  raise  the  temperature 


Ammonia  Refrigeration.  5 

of  one  pound  weight  of  any  particular  sub- 
stance i°  Fahr.,  or  it  may  be  expressed 
as  the  capacity  of  different  substances  for 
heat. 

Scientists  have  proved  that  a  pound  of 
water  has  a  greater  capacity  for  heat  than  a 
pound  of  any  other  known  substance,  and 
therefore  water  is  taken  as  the  standard  of 
comparison,  and  its  specific  heat  at  32°  Fahr. 
is  unity. 

Turpentine  has  a  specific  heat  of  0.472  and 
the  specific  heat  of  mercury  is  0.033  ;  from 
these  figures  it  is  understood  that  to  raise  the 
temperature  of  i  Ib.  of  turpentine  i°  Fahr. 
0.472  B.  T.  U.*  will  be  required,  while  the 
same  weight  of  mercury  will  require  only 
0.033  B.  T.  U.  to  raise  its  temperature  one 
degree. 

If  2  Ibs.  of  water  at  32°  Fahr.  are  heated 
to  42°  Fahr.,  or  through  10°,  they  will  absorb 
(2  Ibs.  x  10°  x  i. ooo  Sp.  Ht.  =)  20  B.  T. 
U's,  but  if  2  Ibs.  of  turpentine  are  heated 
through  the  same  number  of  degrees  they 

*  British  Thermal  Units. 


6  Uieoretical  and  Practical 

will  absorb   only  (2    Ibs.   X   10°  X  0.472   Sp. 
Ht.  =)  9.44  B.  T.  U's. 


EFFECT  OF  TEMPERATURE  AND  PRESSURE 
ON  SPECIFIC  HEAT. 

The  specific  heat  of  substances  varies  with 
varying  conditions  of  temperature  and  pres- 
sure, and  invariably  increases  with  increase 
of  temperature  or  pressure.  The  variation  in 
the  specific  heat  of  water  at  different  temper- 
atures is  so  small  that  it  may  be  passed  un- 
noticed, but  in  the  cases  of  certain  oils  and 
gases  it  is  considerable  :  for  instance,  a  min- 
eral oil  that  has  a  specific  heat  of  0.4503  at 
85°  Fahr.  will  have  a  specific  heat  of  0.4843 
at  120°  Fahr.  Another  point  in  regard  to 
the  specific  heat  of  mineral  oils  is  the  fact 
that  as  the  weight  (specific  gravity)  of  the  oil 
"increases"  the  specific  heat  "decreases." 
Also,  in  the  case  of  paraffin  waxes,  the 
higher  the  melting  point  the  lower  the  spe- 
cific heat. 


Ammonia  Refrigeration.  7 

EFFECT  OF  PRESSURE  ON  SPECIFIC  HEAT 
OF  AMMONIA  GAS. 

The  effect  of  pressure  on  the  specific  heat 
of  ammonia  gas  is  very  marked,  for  whereas 
the  specific  heat  is  only  0.508  when  the  gas 
is  under  a  pressure  of  28  Ibs.  or  less  on  the 
square  inch,  it  is  raised  to  0.532  when  the 
pressure  reaches  80  Ibs.  or  upwards. 

The  specific  heat  of  a  gas  when  expansion 
is  allowed  and  when  mechanical  work  is  per- 
formed is  greater  than  the  specific  heat  of  a 
gas  that  is  not  allowed  to  expand  ;  in  other 
words,  specific  heat  of  a  gas  with  constant 
pressure  is  greater  than  the  specific  heat  of  a 
gas  with  constant  volume.  In  order  to  un- 
derstand this  more  clearly,  the  following 
explanation  must  be  given  : 


SPECIFIC  HEAT   OF  AIR  WITH  CONSTANT 
PRESSURE. 

Let  Figure    I   represent  a  cylinder  with  a 
cross  sectional  area  of  144  square  inches  (one 


8  Theoretical  and  Practical 

square  foot)  tightly  closed  at  both  ends  and 
fitted  with  a  piston,  B,  that  will  move  without 
friction,  and  let  the  piston  weigh 
2, 1 1 6. 2  Ibs.  Now,  if  a  perfect  vacuum 
is  maintained  in  the  space  A,  and  if 
C  contains  I  Ib.  of  air  (=  12.387  cubic 
feet)  at  a  temperature  of  32°  Fahr., 
the  air  will  be  under  a  pressure  of 
14.696  Ibs.  per  square  inch,  and  will 
maintain  the  piston  at  a  height  of 
12.387  feet.  If  this  air  is  now  heated 
to  33°  Fahr. — thus  raising  its  tem- 
perature i°  Fahr. — its  volume  will 
be  increased,  but  the  pressure  will  be 
exactly  the  same  as  before,  because 
the  piston  has  risen  to  make  room 
for  the  increased  volume  of  the  air. 
According  to  Regnault's  determina- 
tions, the  amount  of  heat  that  would 
be  necessary  to  raise  the  temperature 
of  the  air  i°  Fahr.  under  the  above 
conditions,  would  be  0.2379  B.  T.  U. 
Therefore  the  specific  heat  of  air  with 


Fig.  1 

constant  pressure  is  0.2379 


Ammonia  Refrigeration.  9 

SPECIFIC  HEAT  OF  AIR  WITH  CONSTANT 
VOLUME. 

In  the  experiment  just  cited,  not  only  was 
the  temperature  of  the  air  raised  i°  Fahr., 
but,  owing  to  its  expansion,  a  certain  amount 
of  mechanical  work  was  performed  when  the 
piston  was  raised.  Now,  by  heating  the  air 
i°  Fahr.,  its  volume  was  increased  (see  page 

4SS.4  +  33° 
16)   to   (12.387  X  B-f—g.-)   I2.4I226 

cubic  feet,  therefore  the  piston  was  raised 
from  12.387  feet  up  to  12.41226  feet,  or 
through  0.02526  of  a  foot.  As  already  men- 
tioned, the  piston  weighed  2,1 16.2  Ibs.,  there- 
fore the  amount  of  work  done  by  the  expan- 
sion of  the  air  was  2,116.2  Ibs.  X  0.02546, 
height  raised  =  53.4552  foot-pounds.  As  it 
is  known  that  the  mechanical  equivalent  of 
a  unit  of  heat  is  772  foot-pounds,  it  is  seen 
that  the  amount  of  heat  that  was  required  to 
perform  the  mechanical  work  of  raising  the 
piston  was  53.4552  -r-  772  =  0.06924  B.  T.  U. 
Therefore,  if  the  air  had  been  heated  from 
32°  up  to  33°  Fahr.  without  being  allowed 


IO  Theoretical  and  Practical 

to  expand  and  perform  mechanical  work,  the 
amount  of  heat  that  would  have  been  neces- 
sary would  have  been  (0.2379  — 0.06924=) 
0.16866  B.  T.  U.  ;  hence  the  specific  heat  of 
air  with  constant  volume  is  0.16866. 


LATENT  HEAT. 

Latent  heat  is  heat  that  is  hidden  or  is  ab- 
sorbed (without  making  itself  apparent  to 
the  thermometer)  when  a  solid  passes  to  the 
liquid  state,  or  a  liquid  to  the  gaseous  state. 

There  are,  therefore,  two  kinds  of  latent 
heat,  one  being  the  latent  heat  of  liquefac- 
tion and  the  other  the  latent  heat  of  vapor- 
ization. 

LATENT  HEAT  OF  LIQUEFACTION. 

If  I  lb.  of  ice  at  32°  Fahr.  and  I  Ib.  of 
water  at  33°  Fahr.  are  placed  in  separate 
vessels  of  exactly  the  same  size  and  shape, 
and  these  vessels  are  put  in  a  place  that  is 
perfectly  free  from  draughts  and  where  the 
temperature  is  stationary  at,  say,  50°  Fahr., 


Ammonia  Refrigeration.  1 1 

it  will  be  found  that  the  ice  will  take  about 
2 1  times  as  long  to  melt  and  heat  up  to,  say, 
40°  Fahr.  as  the  water  will  take  to  heat  up  to 
the  same  temperature.  Now  it  is  quite  plain 
that  if  both  vessels  are  exposed  to  exactly 
the  same  temperature,  their  contents  must 
each  be  absorbing  heat  at  the  same  rate,  and 
as  the  temperature  of  the  water  in  rising 
from  33°  to  40°,  or  through  seven  degrees, 
only  required  i-2ist  of  the  time  that  the  ice 
took,  the  ice  must  have  absorbed  (7X21)  = 
147°  Fahr.,  but  only  8°  (32°  to  40°)  of  this 
had  been  registered  by  the  thermometer,  and 
therefore  139°  Fhr.  had  become  latent  or  hid- 
den. Of  course  this  is  but  a  crude  method 
of  determining  latent  heat,  and  accurate  de- 
terminations have  fixed  142.4  as  the  latent 
heat  of  ice. 

LATENT  HEAT  OF  VAPORIZATION. 

If  water  is  heated  in  an  open  vessel  it  will 
be  found  that  the  temperature  can  not  be 
raised  above  212°  Fahr.  No  matter  how 
long  the  heat  may  be  applied  the  tempera- 


12  Theoretical  and  Practical 

ture  will  remain  stationary,  although  the 
water  is  constantly  receiving  additional  heat. 
The  heat  thus  hidden  in  the  water  is  called 
the  latent  heat  of  vaporization,  and  if  I  Ib. 
of  steam  at  212°  Fahr.  were  passed  through 
a  condenser  and  converted  into  I  Ib.  of 
water  at  212°  Fahr.  it  would  be  found  that, 
although  the  condensation  of  the  steam  to 
water  had  not  affected  the  temperature  suffi- 
ciently to  be  noticeable  by  the  thermometer, 
the  condenser  would  have  absorbed  966  B. 
T.  U's,  or  sufficient  heat  to  have  raised  the 
temperature  of  over  6^  Ibs.  of  water  from 
60°  Fahr.  up  to  212°  Fahr. 

The  latent  heat  of  vaporization  of  water  is 
therefore  966. 

LATENT  HEAT  OF  WATER. 

It  is  thus  seen  that  to  convert  I  Ib.  of  ice 
at  32°  Fahr.  into  I  Ib.  of  steam  at  212° 
Fahr.  requires : 

Ice  at  32°  to  water  at  32°  (latent)  .  .  142.4 
Water  at  32°  to  water  at  212°  .  .  .  180.0 
Water  at  212°  to  steam  at  212°  (latent)  966.0 


1,288.4  B.  T.  U's; 


A  mmonia 

or  the  amount  of  heat  that  would  reduce 
about  2^/2  Ibs.  of  cast-iron  or  about  9  Ibs.  of 
silver  to  the  molten  state. 

In  making  a  great  many  calculations  in 
regard  to  heat  it  is  necessary  to  make  use 
of  absolute  pressures  and  temperatures. 

ABSOLUTE  PRESSURE. 

Absolute  pressure  is  pounds  per  square 
inch  above  a  vacuum,  and,  as  steam  gauges 
are  adjusted  so  that  the  O,  or  zero  mark, 
represents  the  atmospheric  pressure,  it  is 
necessary  to  add  14.7  Ibs.  to  the  guage  pres- 
sure, in  order  to  convert  it  into  absolute 
pressure. 

ABSOLUTE  TEMPERATURE. 

In  regard  to  absolute  temperature  experi- 
ments have  proved  that  all  pure,  dry  gases 
expand  very  nearly  to  the  same  extent  for 
equal  increments  of  heat,  and  it  therefore 
matters  little  what  gas  is  taken  for  the  pur- 
pose of  explaining  the  principle  on  which 
the  basis  for  absolute  temperatures  has  been 
determined. 


Theoretical  and  Practical 


Let  Fig.  2  be  a  cylinder  closed  at  both 
ends,  and  having  a  cross  sectional  area  of 
144  square  inches  (i  square  foot),  a  depth 
of  about  1 8  inches,  and  a  piston,  B,  capable 


Fig.    2 

of  moving  without  friction.  It  must  now  be 
supposed  that  the  space  C  contains  I  cubic 
foot  of  air  at  a  temperature  of  32°  Fahr.,  and 
that  the  piston,  B,  is  weighted  so  as  to  exert 


Ammonia  Refrigeration.  i$ 

a  pressure  of  14.7  Ibs.  on  the  square  inch, 
while  a  perfect  vacuum  is  maintained  in  A. 
Regnault's  experiments  have  proved  that  if 
the  contents  of  C  are  now  heated  to  212° 
Fahr.,  or  through  180°  Fahr.  (i.  e.,  212° 
—32°),  the  piston  and  its  load  will  be  raised 
0.367  foot,  or  to  D,  and  the  cubic  foot  of  air 
will  be  increased  in  volume  to  1.367  cubic 
feet. 

If  we  start  again  with  the  temperature  at 
32°  Fahr.  and  the  piston  at  E,  and  extract  in- 
stead of  add  1 80°  Fahr.  of  heat  (i.  e.,  cool  down 
the  contents  of  C  to  —  148°  Fahr.),  the  piston 
will  descend  the  same  distance  that  it  rose 
when  the  air  was  heated,  namely,  0.367  foot, 
or  to  F.  The  extraction  of  another  180° 
Fahr.  by  cooling  down  the  contents  of  C  to 
—  328°  Fahr.,  would  cause  the  piston  to  again 
descend  another  0.367  foot,  or  to  G,  and  to 
cause  the  piston  to  descend  to  H  (and  thus 
contract  the  air  in  C  to,  theoretically  speak- 
ing, nothing),  would  necessitate  the  air  being 

1 80 
cooled  down  -—  =  490.4°  Fahr.    below   32° 

Fahr.  or  to  458.4°  Fahr.  below  zero. 


1 6  Theoretical  and  Practical 

ABSOLUTE  ZERO. 

Absolute  zero  is  —  458.4°  Fahr.,  and  an 
absolute  temperature  is  the  absolute  zero 
temperature,  plus  the  ordinary  thermometer 
reading.  The  absolute  temperature  of  a  gas 
at  32°  Fahr.  is  490.4  (458.4  +  32°),  and  if  the 
temperature  were  o°  Fahr.  the  absolute  tem- 
perature would  be  458.4,  while  if  the  temper- 
ature were  —  32°  the  absolute  temperature 
would  be  426.4  (=  458.4  —  32°). 

With  the  aid  of  this  knowledge  it  is  now 
easy  to  understand  how  the  volume  of  gases 
at  different  temperatures  is  computed  by  the 

458.4  +  t 

formula  v  =  V  X  -          T^F*  in  which 
458.4+  1 

V  =  Volume  of  the  gas  at  the  original 
temperature,  T. 

v  =  volume  of  the  gas  at  the  new  tem- 
perature, t. 

EFFECT   OF   PRESSURES   ON  VOLUME  OF 
GASES. 

The  volume  of  gases  is  also  altered  by 
pressure,  and,  according  to  Marriotte,  the 


Ammonia  Refrigeration  17 

volume  of  any  gas  varies  inversely  as  the 
pressure — the  temperature  remaining  con- 
stant. Thus:  one  cubic  foot  of  air  at  10  Ibs. 
absolute  pressure  on  .the  square  inch,  if  sub- 
jected to  an  absolute  pressure  of  100  Ibs.,  will 
be  reduced  in  volume  to  (i  cubic  foot  X  10 
Ibs.  -^  100  Ibs.  =)  o.i  cubic  foot,  provided  the 
work  of  compressing  is  done  without  gener- 
ating heat.  But  it  is  known  that  when  work 
is  done,  heat  is  necessarily  generated,  and 
if  the  cubic  foot  of  air  at  10  Ibs.  absolute 
pressure  is  compressed  to  i-ioth  its  volume 
by  being  subjected  to  an  absolute  pressure 
of  100  Ibs.,  its  temperature  will  be  raised  to 
about  810°  Fahr.  Therefore,  in  calculating 
the  volume  of  a  gas  that  has  been  subjected 
to  pressure,  it  is  necessary  to  take  into  con- 
sideration the  changes  in  volume  caused  by 
both  temperature  and  pressure  together,  and 
the  general  formula  becomes : 

P.  X458._4±! 
P       458.4  +T 

in  which  V,  P  and  T,  and  v,  p  and  t,  are  the 
respective  volumes,  pressures  and  tempera- 


1 8  Theoretical  and  Practical 

tures   of  the  gas  before  and  after  compres- 
sion.    Thus,  if 

I   cubic  foot  of  air =  V 

at  20  Ibs.  Absolute  Pressure =  P 

and   60°  Fahr.  temperature =  T 

is  heated  to 
600°  Fahr.  temperature =  t 

by  being  subjected  to 
200  Ibs.  Absolute  Pressure =  p 

it  will  be  reduced  in  volume  to  : 

Pres.  Temp. 

2O          458.4  -f-   6OO 

i  cubic  foot  x  —  x  --  =  °-2  cubic  ft----  v 


CHAPTER   II. 


THEORY    OF    REFRIGERATION. 

A  CAREFUL  study  of  the  foregoing  pages 
ought  to  have  made  the  two  following  facts 
quite  plain  : 

I.    In  order  to   effect  the   expansion  of  a 


Ammonia  Refrigeration.  19 

gas  it  is  necessary  that  the  gas  should  absorb 
heat. 

2.  The  act  of  compressing  a  gas  generates 
heat. 


FREEZING  BY  COMPRESSED  AIR. 

If  a  compressed  gas  is  re-expanded  it 
practically  absorbs  the  same  amount  of  heat 
that  was  generated  by  compression,  and  the 
re-expanded  gas  will  therefore  be  cooled 
down  to  its  original  (i.  e.,  before  compression) 
temperature.  The  gas  in  this  case  will  sim- 
ply absorb  the  heat  necessary  for  its  re-ex- 
pansion from  itself;  but  if,  on  the  other  hand, 
the  compressed  gas  is  cooled  down  before  it 
is  allowed  to  re-expand,  it  is  very  evident 
that  it  will  not  contain  sufficient  heat  in  itself 
to  effect  its  own  expansion,  and  therefore  it 
will  have  to  extract  the  necessary  heat  from 
its  surroundings,  and  by  so  doing  it  will  pro- 
duce the  sensation  of  cold,  although,  strictly 
speaking,  cold  can  not  be  produced,  as  it  is  a 
negative  condition. 


2O  .  Theoretical  and  Practical 

The  following  example  will  make  the  fore- 
going explanation  plainer: 

i   lb.  of  air  at 14. 7  Ibs.  Abs.  Pres. 

and 60°  Fahr. 

if  compressed  to no  Ibs.  Abs.  Pres. 

will  have  its  temperature  raised   to.. 475°  Fahr. 

This  compressed  air  is  now  cooled  10.65°  Fahr. 

or  through (475°  —  65°) 410°  Fahr. 

As  the  specific  heat  of  air  is  0.238, 
the  number  of  thermal  units  that 
have  been  extracted  from  the  com- 
pressed air  are... (410  X  0.238) 97. 58. 

If  this  cool  compressed  air  is  now  re-ex- 
panded to  its  original  absolute  pressure  of 
14.7  Ibs.,  it  will  have  to  absorb  97.58  B.  T. 
U's.  As  the  extraction  of  170  thermal  units 
from  i  lb.  of  water  whose  temperature  is  60° 
Fahr.  will  convert  the  pound  of  water  into  a 
pound  of  ice,  it  is  evident  that  if  the  i  lb. 
of  above  compressed  air  at  a  temperature 
of  65°  Fahr.  is  expanded  in  a  suitable  appa- 
ratus surrounded  by  (97.584-  170=)  0.574 
lb.  of  water  at  60°  Fahr.  temperature,  the 
water  will  be  converted  into  0.574  lb.  of  ice 
of  32°  Fahr.  temperature. 

The  above  figures  are  only  approximately 


Ammonia  Refrigeration.  21 

correct,  and  are  simply  given  as  an  illustra- 
tion of  the  theory  of  freezing  by  compressing 
and  re-expanding  a  gas  (such  as  air)  that  is 
not  liquefied  by  compression. 

FREEZING  BY  AMMONIA. 

In  considering  the  theory  of  refrigeration 
by  means  of  the  liquefiable  gas  ammonia  it 
will  be  seen  that  the  great  advantage  of  am- 
monia over  air  lies  almost  entirely  in  the 
latent  heat  of  vaporization. 

Suppose  i  Ib.  of  ammonia  gas  at  20  Ibs. 
absolute  pressure  and  32°  Fahr.  is  compressed 
to  110  Ibs.  absolute  pressure,  its  temperature 
will  thereby  be  raised  to  268.6°  Fahr.  If 
the  compressed  gas  is  cooled  to  65°  Fahr. 
its  temperature  will  be  lowered  203.6°,  and 
this  number  of  degrees  multiplied  by  the 
specific  heat  of  ammonia  gas  (which  in  this 
case  is  0.532)  shows  that  108.31  thermal 
units  have  been  extracted  from  the  gas.  But 
if  instead  of  cooling  the  compressed  gas  to 
only  65°  Fahr.  it  is  cooled  to  60°  Fahr.,  it 
will  be  converted  into  a  liquid,  and  as  the 


22  Theoretical  and  Practical 

latent  heat  of  vaporization  of  ammonia  at 
nolbs.  absolute  pressure  is  517.23,  the  fol- 
lowing will  now  be  the  number  of  thermal 
units  extracted.  Temperature  of  compressed 
gas  was  268.6°  Fahr.,  and  if  cooled  to  60° 
Fahr.  its  temperature  will  be  lowered  208.6°. 

Degrees  cooled  X  specific  heat =  110.97  T.  U's. 

Latent  heat  of  vaporization =  517.23        " 


Therefore  total  thermal  units  extracted  =  628.20 

These  figures  show  how  the  advantage  de- 
rived by  the  use  of  ammonia  in  the  place  of 
air  lies  in  the  comparative  ease  with  which 
ammonia  gas  can  be  liquefied,  thereby  allow- 
ing of  use  being  made  of  its  latent  heat  of 
vaporization. 

CHARACTERISTICS  OF  AMMONIA. 

Ammonia  is  a  colorless,  irrespirable  gas, 
with  the  odor  of  hartshorn.  It  is  feebly 
combustible  if  mixed  with  a  large  propor- 
tion of  air,  and  burns  with  a  greenish-yellow 
flame ;  if  mixed  with  about  twice  its  volume 
of  air  it  explodes  with  some  violence.  It 


Ammonia  Refrigeration.  23 

is  only  a  little  more  than  half  the  weight 
oi  air,  is  exceedingly  soluble  in  water,  and 
has  a  very  strong  action  on  copper  and  its 
alloys.  The  characteristics  of  ammonia  ren- 
der it  necessary  that  the  following  precau- 
tions should  be  observed  in  regard  to  the 
handling  of  it  and  in  constructing  an  am- 
n  onia  refrigerating  plant. 

EXPLOSIVENESS. 

Owing  to  the  explosiveness  of  the  gas  it 
i  important  that  any  part  of  an  apparatus 
?  hould  be  thoroughly  aired  before  a  naked 
l.ght  is  brought  near  it.  This  precaution  is 
sometimes  ridiculed  by  those  who,  through 
good  luck  rather  than  good  management, 
have  never  exploded  any  large  volume  of 
the  gas ;  but  the  author  has  personal  knowl- 
edge of  a  case  where  a  man  was  thrown  from 
a  scaffold  by  the  violence  of  an  explosion 
which  took  place  when  the  man  lowered  a 
lighted  candle  into  a  tall  cylinder  used  in 
connection  with  ammonia  refrigeration  by 
the  absorption  process. 


24  Theoretical  and  Practical 

TENDENCY  OF  THE  GAS  TO  RISE. 

When  a  pipe  that  conveys  ammonia  bursts, 
anybody  who  happens  to  be  near  it  should 
keep  his  head  as  low  as  possible  while  effect- 
ing his  escape,  because  the  gas  being  only 
half  as  heavy  as  air  naturally  rises  as  soon 
as  it  is  liberated  into  the  air ;  if  a  man  stood 
erect  he  might  possibly  be  overcome  by  the 
gas,  while  if  he  stooped  he  would,  in  a  great 
many  cases,  escape  without  experiencing  any 
bad  effects. 

SOLUBILITY  IN  WATER. 

As  ammonia  is  exceedingly  soluble  in 
water  (so  much  so  that  i  part  of  water  will 
at  60°  Fahr.  absorb  about  800  parts  of  the 
gas)  the  latter  should  be  used  to  "  kill"  the 
gas  in  the  event  of  any  considerable  quan- 
tity of  strong  ammonia  solution  being  spilt. 
Also,  in  the  case  of  a  man  going  to  the  res- 
cue of  anybody  who  is  overcome  by  the  gas, 
he  should  first  take  the  precaution  of  placing 
a  piece  of  waste  or  rag  soaked  with  water 


Ammonia  Refrigeration.  25 

over  his  nose  and  mouth  before  entering  the 
atmosphere  that  is  impregnated  with  am- 
monia. 

ACTION  ON  COPPER. 

No  part  of  an  ammonia  apparatus  with 
which  the  ammonia  is  liable  to  come  directly 
in  contact  must  be  constructed  of  copper  or 
any  of  its  alloys,  such  as  brass,  bronze,  etc., 
as  the  parts  containing  that  metal  will  be 
rapidly  eaten  away. 

26°  AMMONIA. 

Commercial  liquid  ammonia,  commonly 
known  as  "  spirits  of  hartshorn,"  is  a  solution 
of  ammonia  gas  in  water.  In  the  wholesale 
trade  it  is  sold  in  large  iron  drums,  and  as 
its  usual  strength  is  26°  Beaume,  it  is  known 
as  "  26°  ammonia." 

ANHYDROUS  AMMONIA. 

The  other  commercial  preparation  of  am- 
monia is  liquid  anhydrous  ammonia,  and  it 


26  Theoretical  and  Practical 

must  not  be  confounded  with  the  ordinary 
liquid  26°  ammonia.  The  difference  between 
the  two  is  that  the  liquid  anhydrous  (from 
the  Greek  vdor  —  meaning  without  water) 
ammonia  is  the  pure,  dry,  ammonia  gas 
compressed  to  a  liquid,  while  the  26°  am- 
monia, as  we  have  already  seen,  is  a  solution 
of  the  gas  in  water. 


CHAPTER    III. 

GENERAL    ARRANGEMENT. 

USERS  of  ammonia  refrigerating  machines 
arrange  their  plant  in  a  manner  that  best 
suits  their  special  requirements  or  accommo- 
dations; but  wherever  it  is  practicable  the 
whole  of  the  plant  should  be  as  compact 
as  possible,  so  that  the  possibility  of  loss 
of  refrigerating  effect  due  to  the  absorption 
of  heat  by  long  connections  from  the  sur- 
rounding atmosphere  may  be  reduced  to  a 
minimum. 


Ammonia  Refrigeration.  27 

Figs.  3  and  4  show  the  principal  parts  of 
an  ammonia  plant,  arranged  so  that  the  fol- 
lowing explanation  can  be  easily  followed  and 
understood : 


DESCRIPTION  OF  THE  PLANT. 

When  the  plant  is  in  working  order  the 
liquid  anhydrous  ammonia  is  contained  in  the 
receiver,  E,  and  the  bottom  two  or  three  coi4s 
of  the  condenser;  and  being  under  a  gauge 
pressure  of,  say,  120  Ibs.,  it  flows  through 
the  pipe  F  and  the  manifold  G  to  the  expan- 
sion valves,  H.  Passing  through  the  expan- 
sion valves,  the  ammonia  traverses  a  series 
of  pipes  or  coils  which  are  surrounded  by 
brine  in  the  refrigerator,  I,  and  terminate  in 
the  manifold  K,  that  leads  to  the  suction  of 
the  compressor,  A.  The  suction  of  the  com- 
pressor maintains  a  gauge  pressure  of,  say, 
28  Ibs.  in  these  series  of  pipes,  and  thereby 
relieves  the  ammonia  of  its  high  pressure 
as  soon  as  it  passes  the  expansion  valves. 
Directly  the  liquid  anhydrous  ammonia  ex- 
periences this  relief  of  pressure  it  commences 


28 


Theoretical  and  Practical 


Ammonia  Refrigeration. 


29 


30  Theoretical  and  Practical 

to  boil,  or  vaporize,  and  in  so  doing  it  ex- 
tracts heat  from  the  brine,  which  latter  could 
be  cooled  down  to  the  boiling  point  of  the 
ammonia  due  to  a  suction  pressure  of  28  Ibs., 
namely,  to  14°  Fahr.  By  the  time  the  am- 
monia reaches  the  manifold  K  it  has  been 
entirely  vaporized,  and  therefore  passes  off 
in  the  gaseous  state,  and  entering  the  com- 
pressor by  the  pipe  L  it  is  compressed  and 
then  discharged  through  the  pipe  B  into  the 
separator,  C,  where  any  of  the  oil  (used  for 
lubricating  the  compressor)  or  other  foreign 
matters  that  are  mechanically  carried  for- 
ward by  the  gas  are  separated,  and  the  gas 
then  enters  the  condenser,  D,  where  it  is 
again  liquefied  and,  running  down  into  the 
receiver,  E,  recommences  the  above -de- 
scribed movements. 

CONSTRUCTION   DETAILS — THE 
COMPRESSOR. 

Owing  to  the  heat  that  is  generated  during 
the  compression  of  ammonia  gas  it  is  neces- 
sary that  the  compressor  shall  be  surrounded, 


Ammonia  Refrigeration.  31 

or  jacketed,  with  water,  so  as  to  prevent  the 
overheating  of  the  cylinder,  etc.,  and  undue 
abrasion  of  the  rubbing  surfaces.  The  hori- 
zontal type  of  compressor  is  usually  jacketed 
from  end  to  end,  but  the  heads  are  not  arti- 
ficially cooled. 

A,  Fig.  3,  is  a  half-sectional  end  view  of  a 
horizontal  compressor.  The  cylinder,  a,  and 
jacket,  b,  together  with  the  gas  passages,  f 
and  g,  in  Fig.  4,  are  cast  in  one  piece,  which 
is  bolted  to  the  engine  frame,  G.  The  pas- 
sage g  supplies  the  two  suction  valves,  d  and 
k,  while  the  discharge  valves,  e  and  /,  connect 
with  the  passage  f.  The  jacket  is  supplied 
with  water  by  the  pipe  /,  the  water  filling  up 
the  space  h  and  overflowing  through  r.  The 
cylinder  heads,  i  i,  which  contain  the  valves, 
ports  and  passages  leading  to  /  and  g,  are 
held  in  place  by  the  bolts,  s. 

In  the  vertical  type  of  compressor  the 
water-jacket  is  built  so  that  the  water  not 
only  surrounds  the  compressor  cylinder  but 
also  entirely  submerges  the  cylinder  head 
and  its  valves.  The  relative  efficiency  of 
the  two  types  of  compressors  will  be  com- 


32  Theoretical  and  Practical 

pared    under   the    heading   "  Indicator   Dia- 
grams." 


STUFFING-BOXES. 

One  of  the  principal  sources  of  loss  of 
ammonia  in  a  refrigerating  plant  is  in  the 
stuffing-boxes  of  the  compressor.  The  stuf- 
fing-boxes in  some  of  the  vertical  types  of 
compressors  are  packed  with  lead  or  babbitt- 
metal  rings  cut  with  a  bevel,  so  that  when 
they  are  subjected  to  pressure  every  alter- 
nate one  hugs  the  piste n-rod,  while  the 
others  are  pressed  tightly  against  the  inner 
surface  of  the  stuffing-box,  thus  forming  a 
tight  yet  smooth  working  packing.  In  the 
vertical  compressor,  which  is  only  single-act- 
ing, the  pressure  on  the  packing  dc3s  not 
exceed  28  Ibs.  on  the  square  inch,  while  with 
the  horizontal  compressor,  which  is  double- 
acting,  the  pressure  may  reach  and  even 
exceed  165  Ibs.,  according  to  the  tempera- 
ture of  the  condensing  water.  For  this 
reason  it  is  necessary  that  the  packing  for 
stuffing-boxes  in  a  horizontal  compressor 


Ammonia  Refrigeration.  33 

stuffing-box  shall  be  deep.  The  depth  is 
usually  12  inches,  and  the  annular  space  be- 
tween the  piston-rod  and  the  inside  of  the 
box  is  about  %  of  an  inch.  It  requires  a 
considerable  amount  of  attention  which  is 
more  or  less  proportional  to  the  condensing 
pressure,  but  more  especially  to  the  kind  of 
packing  that  is  used,  and  it  is  with  a  sense 
of  the  benefit  that  the  user  will  derive  that 
"Common  Sense,"  "Oarlock's,"  and  "  Sel- 
den's  "  packings  are  recommended  as  being 
specially  suitable  (if  used  conjointly)  for  hori- 
zontal compressor  stuffing-boxes.  The  most 
satisfactory  way  to  employ  this  combination 
packing  is  to,  first  of  all,  pack  the  stuffing- 
box  to  a  depth  of  5  to  5  ^  inches  with  Com- 
mon Sense  packing ;  then,  having  placed  the 
perforated  ring  in  position,  half  fill  the  rest 
of  the  box  with  Garlock's  packing  and  finish 
off  with  Selden's  packing. 

The  packing  should  be  driven  tightly 
home,  piece  by  piece,  and  then  the  gland 
should  be  screwed  on  only  hand-tight,  so  as 
to  allow  the  packing  room  to  expand  and  fill 
the  spaces  without  undue  pressure.  If  the 


34  Theoretical  and  Practical 

packing  is  forced  into  the  stuffing-box  by 
means  of  the  gland,  and  is  not  allowed 
room  to  expand,  it  will  last  but  a  very 
short  time,  and  give  trouble  as  long  as  it 
does  last 


SPECIAL  LUBRICATION. 

The  hot  ammonia  gas  under  high  pressure 
will  cut  through  the  best,  packing  in  a  very 
short  time  if  a  liberal  supply  of  oil  is  not 
forced  into  the  stuffing-box  at  intervals  of  an 
hour  or  so.  To  effect  the  thorough  lubrica- 
tion of  the  packing  it  is  necessary  that  a  hole 
shall  be  tapped  in  the  centre  (longitudinally) 
of  the  stuffing-box,  which  is  then  connected 
by  a  i^-inch  pipe  with  a  small  hand  forcr- 
pump.  The  packing  is  divided  into  two 
portions  by  a  perforated  iron  ring,  which 
ring  is  directly  opposite  the  above-men- 
tioned hole,  so  that  when  the  oil  is  deliv- 
ered by  the  pump  it  is  distributed  through 
the  perforations  to  the  packing  on  either 
side  of  the  ring. 


Ammonia  Refrigeration.  35 

OIL   FOR   LUBRICATION. 

On  no  account  must  any  animal  or  vege- 
table oils  be  used  for  lubricating  the  com- 
pressor, because  as  soon  as  any  of  these  oils 
come  in  contact  with  the  ammonia  they  will 
form  soaps  that  will  give  endless  trouble  and 
annoyance.  Nothing  but  a  mineral  oil  of 
high  viscosity  and  guaranteed  purity  should 
be  used. 

CLEARANCE  SPACE,  ETC. 

It  is  very  essential  that  there  shall  be  no 
unnecessary  spaces,  such  as  screw-slots,  deep 
ports,  etc.,  on  the  inside  of  the  compressor 
cylinder,  and  the  clearance  space  between  the 
piston  and  cylinder  head  should  not  exceed 
i-3?d  to  3-64ths  of  an  inch.  If  attention  is 
not  paid  to  these  particulars  too  much  gas 
will  remain  in  the  cylinder  after  the  piston 
has  completed  its  stroke,  and  the  re-expan- 
sion of  this  clearance-space  gas  as  the  piston 
recedes  will  greatly  diminish  the  working 
capacity  of*  the  cylinder. 


36  Theoretical  and  Practical 

SUCTION  AND  DISCHARGE  VALVES. 

The  suction  and  discharge  ports  are  closed 
by  poppet  valves.  The  discharge  valve,  Fig. 
5,  screws  into  the  outside  of  the  cylinder 
head,  and  the  spring,  a,  presses  the  valve 


Fig.  5 


Fig.  6 


against  the  seat  on  the  inside  of  the  head. 
The  suction-valve,  Fig.  6,  screws  into  both 
the  outside  and  inside  of  the  cylinder  head, 
and  the  gas  in  G,  Figs.  3  and  4,  passes  in 


Ammonia  Refrigeration.  37 

through  the  holes,  a,  in  its  passage  to  the 
cylinder.  The  spring,  b,  is  held  in  its  place 
by  the  nut,  c. 


EFFECT  OF  EXCESSIVE  VALVE-LIFT. 

The  lift  of  the  valves  is  of  very  great  im- 
portance, as  it  materially  affects  the  refriger- 
ating effect  of  a  machine.  If  the  lift  is  too 
great  the  valve  will  not  act  with  sufficient 
quickness,  and  especially  is  this  so  in  the 
case  of  high-speed  compressors,  in  which 
an  additional  valve-lift  of  y&  of  an  inch  will 
cause  a  diminution  of  one  ton  refrigerating 
effect  in  24  hours. 


REGULATION  OF  VALVE-LIFT. 

The  lift  of  the  discharge  valve  is  regulated 
by  the  plug,  b,  against  which  the  valve-stem 
strikes,  the  distance  between  the  striking 
surfaces  being  regulated  by  the  thickness  of 
gasket,  c.  In  the  case  of  the  suction-valve, 


38  Theoretical  and  Practical 

the  lift  is  regulated  by  means  of  an  iron 
sleeve  around  the  valve-stem  against  which 
the  nut,  c,  strikes  when  the  valve  opens. 


CHAPTER    IV. 

THE      SEPARATOR. 

OWING  to  the  large  volume  of  oil  that  is, 
or  should  be,  used  for  lubricating  the  stuf- 
fing-box of  the  compressor,  it  is  evident  that 
a  considerable  quantity  of  it  must  pass  into 
the  cylinder  and  be  carried  through  the  dis- 
charge valves  by  the  ammonia  gas.  If  this 
oil  were  allowed  to  pass  into  the  condenser  it 
would  soon  find  its  way  into  the  rest  of  the 
apparatus,  and  would  cause  trouble  by  chok- 
ing up  the  expansion  valves,  etc.  ;  therefore, 
with  a  view  to  obviating  this  annoyance,  a 
separator  is  interposed  between  the  com- 
pressor and  condenser.  The  usual  form  of 
separator  is  an  iron  cylinder  about  18  inches 


Ammonia  Refrigeration.  39 

in  diameter  and  from  18  to  36  inches  high. 
The  ammonia  gas  enters  by  a  connection  on 
one  side  and  leaves  by  a  connection  on  the 
opposite  side.  The  connections  are  usually 
3  or  4  inches  from  the  top,  and  the  gas  com- 
ing in  contact  with  the  side  of  the  cylinder  is 
freed  of  the  most  of  its  oil  and  passes  on  to 
the  condenser,  while  the  oil  falls  to  the  bot- 
tom of  the  separator.  This  and  most  other 
forms  of  separators  are  very  imperfect,  for 
the  reason  that  they  are  not  supplied  with 
sufficient  contact-surface  and  are  not  kept 
sufficiently  cool.  The  gas  when  it  passes 
through  the  separator  is  at  a  high  temper- 
ature, say  200°  Fahr.,  and  consequently  the 
oil  held  in  suspension  is  exceedingly  limped 
and  light  in  weight,  and  has  not  any  great 
tendency  to  separate  from  the  gas.  The 
author  w7ould,  therefore,  advise  the  construc- 
tion of  a  separator  on  the  principle  shown 
in  Fig.  7.  The  cast-iron  cylinder,  A,  with 
its  inlet,  E,  and  outlet,  F,  opposite  one  an- 
other, has  its  cover,  B,  and  contact  plates,  C, 
cast  in  one  piece,  and  these  are  arranged  so 
that  when  the  gas  impinges  on  them  it  is 


Theoretical  and  Practical 


Fig.  VI 1 


,H   .v 


1 

1 

1 

s\ 

c 

§ 

1 

I 

\ 

>Ws^^^^ 

.ML 


SECTION  THRO,  X.  Y. 


Ammonia  Refrigeration.  41 

distributed  over  a  large  surface  and  is  forced 
against  the  side  of  the  cylinder  in  its  zigzag 
passage  from  E  to  F.  The  oil  in  striking 
against  these  division  plates  will  separate 
from  the  gas  far  more  readily  than  if  it 
meets  with  no  obstruction,  but  even  with  the 
aid  of  the  contact  plates  the  separator  will 
not  effect  a  perfect  separation  unless  the  oil 
is  rendered  more  viscous  so  as  to  increase 
its  tendency  to  adhere  to  the  plates,  etc. 
This  can  be  easily  accomplished  by  making 
use  of  the  water-jacket,  D,  which  will  keep 
the  separator  cold  enough  to  make  the  oil 
separate  and  fall  to  the  bottom.  The  bot- 
tom of  the  separator  may  be  connected  with 
the  compressor  so  that  the  separated  oil  may 
be  used  over  again ;  but  this  connection  is 
of  little  or  no  use  with  double-acting  com- 
pressors, because  pieces  of  packing,  etc.,  that 
find  their  way  from  the  stuffing-box  into  the 
compressor  and  thence  into  the  separator 
will  soon  choke  it  up.  The  separator  should 
be  periodically  cleaned,  the  cover,  B,  and 
plates,  C,  being  raised  by  the  ring,  G,  after 
the  water  has  been  run  off  from  the  jacket 


42  Theoretical  and  Practical 

by  the  cock,  I.  On  no  account  must  the 
inlet  to  the  separator  look  down,  because  the 
gas  will  then  impinge  on  the  oil  lying  in  the 
bottom,  and  will  be  likely  to  become  more 
contaminated  with,  rather  than  freed  of,  the 
oil. 

THE  CONDENSER. 

The  shape  of  the  condenser  tank  affects 
the  efficiency  of  the  condenser  to  some  ex- 
tent :  it  should  be  deep  and  narrow  rather 
than  long  and  shallow,  so  that  there  may  be 
as  great  a  distance  as  possible  between  the 
more  or  less  warm  water  on  the  surface  and 
the  cold  water  that  is  admitted  at  the  bot- 
tom. Another  important  point  is  to  see  that 
the  water  is  properly  distributed  when  it 
enters  the  bottom  of  the  condenser,  and  not 
allowed  to  all  run  in  at  one  point,  as  in 
the  case  of  a  discharge  through  an  open-end 
pipe. 

CONDENSER- WORM. 

The  condenser- worm  or  piping  through 
which  the  ammonia  passes  should  consist  of 


Of  TH3J 

'UNIVERSITY; 

Ammonia  Refriger&tt8g~£z.S2^%$ 

about  one-third  of  2-inch,  one-third  of  I  Y^- 
inch,  and  one-third  of  i-inch  pipe.  This 
gradual  decrease  in  the  size  of  the  pipe  will 
give  far  less  "  excessive"  condensing  pressure 
than  when  the  gas  passes  from  a  manifold 
into  a  series  of  three  or  four  separate  one- 
inch  worms.  The  friction  of  the  gas  in  pass- 
ing through  a  2-inch  pipe  is  less  than  when 
the  gas  passes  through  a  number  of  pipes 
whose  aggregate  areas  are  equal  to  a  2-inch 
pipe.  Another  point  is,  it  is  quite  unneces- 
sary to  have  the  same  cross-sectional  area  for 
the  exit  as  for  the  inlet  pipe,  because  the 
volume  of  the  liquid  anhydrous  ammonia 
passing  through  the  exit  is  only  about  I -75th 
of  the  volume  of  the  gas  that  passes  through 
the  inlet  pipe. 

RECEIVER. 

The  receiver  should  be  capable  of  holding 
4  Ibs.  of  liquid  anhydrous  ammonia  for  every 
24-hour-ton  maximum  capacity  of  the  ma- 
chine. That  is  to  say,  if  the  machine  has  a 
maximum  capacity  of  65  tons  of  ice  in  24 


44  Theoretical  and  Practical 

hours,  the  receiver  should  be  capable  of 
holding  65  X  4  =  260  Ibs.  of  liquid  anhy- 
drous ammonia. 


REFRIGERATOR  OR  BRINE  TANK. 

The  arrangement  of  the  piping  in  the  re- 
frigerator is  different  from  that  in  the  con- 
denser. By  referring  to  Fig.  3  it  will  be 
seen  that  the  liquid  ammonia  entering  the 
series  of  piping  at  the  manifold  G  descends 
by  the  vertical  pipes,  T,  and  then  passes 
upward  through  the  coils,  U,  before  it  is 
taken  into  the  suction  manifold  K.  The 
object  of  arranging  the  piping  in  this  way 
is  to  insure  the  thorough  vaporization  of  the 
liquid  ammonia  when  the  brine  has  become 
cooled  down  to  a  point  near  to  the  ooiling 
point  of  the  ammonia  due  to  any  given  suc- 
tion pressure,  and  the  vaporization  is  thor- 
oughly effected  because  any  liquid  ammonia 
that  does  not  vaporize  will  not  pass  upwards, 
and  therefore  the  gaseous  or  vaporized  am- 
monia has  to  bubble  through  it,  and  the 
liquid  thereby  absorbs  sufficient  heat  from 


Ammonia  Refrigeration.  45 

the  gaseous  ammonia  to  effect  the  vaporiza- 
tion of  the  whole.  If  the  liquid  ammonia 
passed  in  at  the  higher  and  out  at  the  lower 
extremity,  as  in  the  case  of  an  ordinary  con- 
denser-worm, a  large  quantity  of  the  am- 
monia would  pass  through  in  the  liquid  form, 
as  the  warmer,  or  gaseous  portion,  would  not 
be  brought  so  intimately  in  contact  with  it. 
The  refrigerator  should  be  thoroughly  insu- 
lated, and  for  this  purpose  it  should  be  sur- 
rounded by  a  wooden  jacket  so  that  there  is 
a  space  of  about  3  to  6  inches  between  the 
refrigerator  and  the  inside  of  the  jacket,  and 
this  space  should  be  filled  with  mineral-wool, 
charcoal,  sawdust,  or  any  other  good  non- 
conductor. 

SIZE    OF   PIPE    AND   AREA    OF    COOLING 
SURFACE. 

The  size  of  pipe  and  total  cooling  surface 
exposed  to  the  brine  very  materially  affect 
the  economical  running  of  a  refrigerating 
plant,  and  practical  results  have  demon- 
strated without  doubt  that  coils,  or  worms, 
made  of  2-inch  pipe  are  far  more  econom- 


46 


Theoretical  and  Practical 


ical  in  regard  to  the  use  of  steam,  etc.,  than 
i -inch  pipe.  The  total  length  of  piping  in 
contact  with  the  brine  should  be  sufficient 
to  give  a  mean  cooling  surface  of  50  to  55 
square  feet  per  24-hour-ton  maximum  ca- 
pacity. 

EXPANSION  VALVES. 

The  expansion  valves  are  of  the  spindle 
type  as  shown  in  Fig.  8,  and  should  be 
made  of  the  best  quality  of  cast-iron. 


Fig.  VIII 


Ammonia  Refrigeration.  47 


A  —  Manifold  when  number  of  valves  are  connected 
by  flanges,  B,  B. 

C  and  D  =  Inlet  and  Outlet  Passages. 

E  =  Flange  connecting  valve  with  coil  in  refrigerator. 

F  =  Needle-Valve. 

G  =  Plug  to  simplify  cleaning  passages  in  case  of 
stoppage. 

WORKING   DETAILS.  —  CHARGING  THE 
PLANT  WITH  AMMONIA. 

In  order  to  charge  a  new  or  at  any  rate 
an  empty  plant  with  ammonia  it  is  first  of 
all  necessary  to  expel  the  air.  This  is  done 


48  Theoretical  and  Practical 

by  opening  all  the  valves  and  cocks  with  the 
exception  of  O,  P,  and  S,  which  latter  are 
tightly  closed,  and  allowing  the  compressor 
to  exhaust  the  air  from  D,  E,  F,  G,  I,  K,  and 
L,  and  discharge  it  through  the  open  cock 
N,  until  the  combination  vacuum-pressure 
gauge  connected  to  the  suction,  of  the  com- 
pressor shows  that  the  engine  is  not  capable 
of  exhausting  the  apparatus  any  further ;  the 
cock  N  and  valve  H  are  then  closed  and 
the  valve  O  opened.  The  drum  of  anhy- 
drous ammonia  (if  an  anhydrous  ammonia 
generating  apparatus  is  not  included  in  the 
plant)  is  now  connected  with  the  cock  S, 
which  latter  is  then  opened  to  allow  the 
compressor  to  transfer  the  ammonia  from 
the  drum.  When  the  plant  is  charged  the 
cock  S  is  closed  and  the  valves  H  ars  then 
opened  sufficiently  to  allow  the  compressor 
to  maintain  the  suction  pressure  correspond- 
ing to  the  required  brine  temperature,  which 
will  be  alluded  to  later. 


Ammonia  Refrigeration.  49 

CHAPTER  V. 

AMMONIA  TO  BE  GRADUALLY  CHARGED. 

THE  plant  should  not  be  charged  with 
more  than  60  per  cent,  of  its  full  comple- 
ment of  ammonia  at  its  first  charging  be- 
cause it  is  impossible  to  exhaust  the  whole 
of  the  air  from  the  plant  by  means  of  the 
compressor,  and  the  only  way  to  get  entirely 
rid  of  the  air  is  by  displacement.  This  is 
effected  by  very  cautiously  opening  the  cock 
P  once  or  twice  a  day  and  allowing  the  air 
to  escape,  at  the  same  time  taking  every  pre- 
caution to  prevent  undue  loss  of  ammonia. 
After  the  air  has  been  displaced  a  fresh 
quantity  of  ammonia  is  pumped  into  the 
plant  in  the  manner  above  described,  and 
the  next  day  the  same  operation  is  gone 
through  again,  until  at  the  end  of,  say,  six 
days,  the  full  complement  of  ammonia  has 
been  charged.  In  this  manner  the  whole 
of  the  air  is  effectually  expelled  with  but  a 
slight  loss  of  ammonia.  An  experienced 
man  can  easily  tell  from  the  general  condi- 


5O  Theoretical  and  Practical 

tions  and  working  of  the  plant  when  suffi- 
cient ammonia  has  been  charged  ;  but  as  the 
uninitiated  might  experience  some  difficulty 
in  ascertaining  whether  the  plant  was  suffi- 
ciently charged,  the  following  method  has 
been  formulated  for  calculating  the  quantity 
of  ammonia  that  constitutes  a  full  charge. 

Suppose  the  maximum  capacity  of  plant  is 
65  tons  of  ice  per  24  hours,  and  that  the  sizes 
of  the  different  parts  are  as  follows  : 


Connection  from           ^ 
Compressor    to   Sepa-  (  B  2  in. 

rator.                           ) 
Separator                                  C           24  " 

LENGTH. 
10  ft.      - 

2     " 

CAPAC- 
ITY. 
CUBIC 

)    FT" 
k  4.1.  1 

•Containing   \ 
Ammonia   \    D1  ..i^    " 
Condenser-         as  gas.         ) 
Worm.        j  Containing  \ 
Ammonia    >    D2..i>£    " 
-    as  liquid.    ) 
Receiver                                     -E  24    *' 

2800     " 
700     " 

3    " 

1 

Connection  from  Receiver  ^ 
to  Refrigerator  ^ 

18-3 

Manifold    for    Expansion  )     p           2    « 

6    " 

Valves                               \ 

Refrigerating  Piping  T  &  U   1)4    " 
Connection  from                \ 
Refrigerator  to                   C  K&L...2    " 
Compressor                         ) 

6000    " 
o   «     1 

J 

>I00.3 

Ammonia  Refrigeration.  5  I 

The  parts  B,  C,  and  D1  will  contain  am- 
monia in  the  gaseous  state  at  a  gauge  pres- 
sure of,  say,  1 20  Ibs.  and  average  temperature 
of  80°  Fahr. 

The  parts  D2,  E,  F,  and  G  will  contain 
liquid  anhydrous  ammonia. 

The  parts  T,  U,  K,  and  L  will  contain  gas- 
eous ammonia  at  a  gauge  pressure  of  28  Ibs. 
and  an  average  temperature  of  1 5°  Fahr. 


TABLE 

I. 

GAUGE 
PRES- 
SURE. 

TEMPERATURE  OF   GAS. 

66°            740 

80° 

84°         9< 

Do          95o 

ir^i,.           ~r   »    TU     _r  r*    _    :       r<—  1_-      T7._^ 

80 

3-470 

85 

3.292 

90 

3-!3i 

95 

3-°35 

100 

2.900 

, 

105 

2.785 

IIO 

2.695 

115 

2.590 

120 

2.490 

125 

2.418 

130 

2-333 

135 

2.252 

140 

2.204 

145 

2.134 

ISO 

2.088 

!55 

2.037 

52  Theoretical  and  Practical 

From  Tables  I.  and  V.  it  will  be  seen 
that  the  volumes  of  the  ammonia  gases  at 
the  above  pressures  and  temperatures  of  120 
Ibs.  and  80°  Fahr.  and  28  Ibs.  and  15°  Fahr. 
are  respectively  2.490  and  10.763  cubic  fee*- 
per  pound  of  ammonia  ;  therefore  the  amount 
of  ammonia  required  to  charge  the  plant  is  : 

B,  C,  and  D1 =  (41. 1  —  2.49)  16^  Ibs. 

D2,  E,  F,  andG =(18.3x38-66*)          707^    " 

T,  U,  K,  and  L =  (100.3—10.763)  9^    " 


Total,  733^  Ibs. 


JACKET-WATER  FOR  COMPRESSOR. 

The  amount  of  jacket-water  necessary  for 
the  compressor  varies  according  to  the  con- 
densing pressure.  With  a  low  condensing 
pressure — say  90  to  105  Ibs.  gauge  pressure 
— 10  to  15  gallons  of  water  per  hour  per  24- 
hour  ton  refrigerating  effect  will  usually  be 
found  ample,  but  when  the  condensing  pres- 
sure reaches,  say,  140  to  150  Ibs.,  the  amount 
of  water  will  have  to  be  increased  to  about 

*  Weight  of  a  cubic  foot  of  liquid  anhydrous  ammonia, 


Ammonia  Refrigeration.  53 

45  to  50  gallons  per  hour  per  24-hour  ton 
refrigerating  effect. 

JACKET- WATER  FOR  SEPARATOR. 

The  amount  of  water  used  in  the  separa- 
tor jacket  should  be  as  large  as  possible,  and 
so  that  the  water  may  not  be  wasted  or  be- 
come expensive,  the  overflow-pipe,  H,  should 
be  continued  down  midway  into  the  con- 
denser, where  the  water  should  be  distributed 
and  used  along  with  the  condensing  water 
that  is  admitted  at  the  bottom  of  the  con- 
denser. 

CONDENSING  WATER. 

As  the  pressure  against  which  the  com- 
pressor has  to  work  is  regulated  almost  en- 
tirely by  the  temperature  of  the  condensed 
ammonia,  it  is  obvious  that  the  lower  the 
temperature  of  the  condensed  ammonia,  the 
greater  the  saving  in  the  wear  and  tear  of 
the  engine,  in  the  use  of  steam  and  con- 
sequently the  consumption  of  coal,  will  be. 
The  quantity  and  the  temperature  of  the 


54  Theoretical  and  Practical 

condensing  water  are,  therefore,  points  that 
need  careful  consideration.  The  manufac- 
turer who  has  to  use  the  city  water-supply 
for  condensing  purposes  can  not,  under  or- 
dinary circumstances,  economically  cool  the 
ammonia  to  a  lower  temperature  than  55° 
to  60°  Fahr.  during  the  winter  months,  and 
65°  to  75°  Fahr.  during  the  summer  months, 
because,  should  he  increase  his  supply  of 
water  sufficiently  to  reduce  the  temperature 
of  the  ammonia,  say  10°  below  the  above 
figures,  he  would  at  once  incur  an  extra  ex- 
pense that  would  not  be  warranted  by  the 
resulting  increase  in  the  refrigerating  effi- 
ciency of  the  plant.  This  increased  expen- 
diture can,  however,  be  overcome  if  the 
following  plan  is  adopted  : 

LESSENING  THE   COST  FOR  CONDENSING 
WATER. 

Instead  of  supplying  the  steam-boilers  in 
the  establishment  with  the  whole  of  their 
water  direct  from  the  main,  the  author  ad- 
vises arrangements  being  made  to  draw  the 


Ammonia  Refrigeration.  55 

boiler  water-supply  from  the  overflow  of  the 
ammonia  condenser,  then  making  up  the 
deficiency  from  that  source  by  drawing  from 
the  main.  This  method  of  working  would 
be  beneficial  in  every  respect,  because  in  the 
first  place,  the  water  in  passing  through  the 
condenser  will  receive  a  certain  amount  of 
heat  which  is  distinctly  an  advantage,  as 
boiler-water  is,  or  should  be,  heated  before 
entering  the  boiler.  Secondly,  if  the  whole 
or  a  part  of  the  water  required  for  the  boilers 
is  taken  from  the  ammonia-condenser  over- 
flow, the  cost  of  condensing  the  ammonia  is 
practically  reduced  to  «//,  because  the  boilers 
have  to  be  supplied  with  water,  and  the  fact 
that  that  necessary  supply  has  been  pre- 
viously used  for  condensing  purposes  in  no 
way  increases  the  cost  after  the  first  cost  of 
putting  up  the  system  of  piping  for  convey- 
ing the  water  has  been  paid  for.  Thirdly, 
the  effect  of  the  use  of  a  superabundance  of 
condensing  water  will  be  a  reduction  of,  at 
least,  30  to  40  Ibs.  per  square  inch  in  the 
condensing  pressure  and  a  corresponding 
saving  in  steam. 


56  Theoretical  and  Practical 

QUANTITY  OF  CONDENSING  WAVER 
NECESSARY. 

If  the  temperature  of  the  water  supplied 
to  the  condenser  is  5 5°  to  60°  Fahn,  and  the 
temperature  of  the  overflow  or  outlet  water 
is  85°  to  90°  Fahr.,  the  quantity  of  water  that 
will  be  required  will  be  about  0.9  gallons  per 
minute  per  24-hour  ton  of  ice  ;  but  if  the 
temperature  of  the  overflow  were  oily  70° 
to  75°  Fahr.  (the  inlet  temperature  being 
5  5°  to  60°),  the  quantity  of  water  that  would 
be  necessary  would  be  about  2^  gallons  per 
minute  per  24-hour  ton  of  ice.  This  reduc- 
tion of  fifteen  degrees  in  the  temperature  of 
the  overflow  means  a  reduction  of  30  to  40 
Ibs.  in  the  condensing  pressure,  and  if  the 
ammonia  leaves  the  condenser  at  the  tem- 
perature of  the  inlet  water,  a  minimum  con- 
densing pressure  and  large  saving  in  steam 
will  result. 

Loss   DUE   TO   HEATING   OF  CONDENSED 
AMMONIA. 

One  very  weak  point  and  very  surprising 
oversight  in  the  management  of  a  great  num- 


Ammonia  Refrigeration.  57 

her  of  refrigerating  plants  is  the  fact  that, 
although  manufacturers  often  go  to  a  deal 
of  expense  in  order  to  condense  and  cool 
the  ammonia  to  the  lowest  possible  tempera- 
ture, they  entirely  ignore  the  importance  of 
making  arrangements  to  maintain  that  low 
temperature  until  the  ammonia  reaches  the 
refrigerator.  The  receiver,  and  a  consider- 
able length,  if  not  the  whole,  of  the  piping 
through  which  the  anhydrous  ammonia  has 
to  pass  on  its  way  to  the  refrigerator  are,  as 
a  rule,  situated  in  the  engine-room — which 
is  not  usually  the  coolest  of  places — and  the 
temperature  of  the  ammonia  is  consequently 
often  raised  5,  10,  15,  or  even  20  degrees 
(above  the  temperature  at  which  it  left  the 
condenser)  before  it  reaches  the  refrigerator ; 
and  as  these  5  to  20  degrees  gain  in  tem- 
perature mean  a  loss  of  from  J^  to  I  J^  ton 
refrigerating  effect  per  24  hours,  on  a  65 -ton 
machine,  it  seems  as  though  it  would  be  ad- 
vantageous to  have  the  receiver  and  piping 
covered  with  a  cheap  non-conducting  mate- 
rial, so  as  to  take  full  advantage  of  the  bene- 
fits resulting  from  a  liberal  water-supply  to 


58  Theoretical  and  Practical 

the  condenser,  and  thus  prevent  an  unneces- 
sary waste. 

Loss  DUE. 

It  might  be  advisable  to  here  refer  to  an- 
other source  of  needless  loss  which  has  even 
a  greater  effect  on  the  refrigerating  efficiency 
of  a  machine  than  the  case  just  considered. 

SUPERHEATING  AMMONIA  GAS. 

It  is  the  loss  incurred  by  the  ammonia  gas 
absorbing  heat  in  the  transit  from  the  re- 
frigerator to  the  compressor.  Some  people 
argue  that  it  is  absurd  to  go  to  any  expense 
for  the  purpose  of  preventing  that  gas  from 
absorbing  heat,  as  it  is  heated  up,  any  way, 
as  soon  as  it  enters  the  compressor.  Others, 
again,  consider  that  any  heat  absorbed  by 
the  gas  simply  means  that  a  few  more  ther- 
mal units  will  have  to  be  extracted  from  the 
gas  when  it  passes  into  the  condenser.  If 
these  people  would  just  take  time  to  think, 
they  would  at  once  see  that  the  higher  the 
temperature  of  the  gas  is  before  it  enters 


Ammonia  Refrigeration.  59 

the  compressor  the  greater  the  volume  of  a 
given  weight  must  be,  and  therefore  the 
compressor,  although  circulating  or  pumping 
the  same  volume,  will  not  circulate  so  great 
a  weight ;  and  as  the  refrigerating  efficiency 
of  a  machine  is  proportional  to  the  weight 
of  ammonia  circulated,  it  is  obvious  that  the 
higher  the  temperature  of  the  gas  before  it 
enters  the  compressor,  the  smaller  the  re- 
frigerating efficiency  of  the  machine  will  be, 
the  suction  pressure  being  the  same  in  both 
cases.  The  effect  of  covering  the  ammonia 
pipes  is  more  particularly  dealt  with  under 
the  heading  "  Directions  for  Determining 
Refrigerating  Efficiency." 


CHAPTER   VI. 

EXCESS    CONDENSING    PRESSURE. 

THE  condensing  pressure,  when  the  appa- 
ratus is  working,  is  always  greater  than  the 
theoretical.  This  "excess"  pressure  is  due 
almost  entirely  to  the  confining  of 


60  Theoretical  and  Practical 

heated  gaseous  ammonia  in  the  more  or  less 
limited  space  of  the  coils  of  the  condenser, 
and  varies  greatly  according  to  circum- 
stances. When  running  at  a  low  suction 
pressure,  say  atmospheric  pressure,  the  ex- 
cess condensing  pressure  should  not  be  over 
5  to  10  Ibs.,  but  when  running  with  a  suction- 
gauge  pressure  of  20  to  28  Ibs.  the  excess 
pressure  will  vary  from  40  to  60  Ibs. 


CAUSE  OF  VARIATION  IN  EXCESS 
PRESSURES. 

The  reason  why  there  is  such  a  large  vari- 
ation in  the  excess  pressure  is  obvious :  with 
28  Ibs.  suction-gauge  pressure,  the  com- 
pressor is  pumping  a  three  times  greater 
weight  of  gas  than  it  would  pump  if  the  gas 
were  under  only  an  atmospheric  pressure, 
and  therefore  the  condenser  is  crowded  to 
a  greater  extent  in  the  former  than  in  the 
latter  case.  It  may  be  argued  that  if  the 
compressor  is  forcing  into  the  condenser  a 
three  times  greater  weight  of  ammonia  in 


Ammonia  Refrigeration.  61 

one  case  than  in  another,  the  condenser  at 
th^  same  time  will  be  relieved  by  the  ex- 
pansion valves  of  a  three  times  greater 
weight  of  liquid  ammonia,  and  one  will  thus 
counterbalance  the  other.  It  is,  of  course, 
true  that  the  weight  of  liquid  ammonia  pass- 
ing the  expansion  valves  will  be  the  same 
as  the  weight  of  ammonia  gas  entering  the 
condenser  from  the  compressor;  but  as  the 
volume  of  a  given  weight  of  the  gas  at  con- 
densing temperature  and  pressure  is  about 
75  times  greater  than  the  volume  of  the 
same  weight  of  liquid  ammonia,  it  is  plain 
that  if  instead  of  pumping  in  75  volumes 
of  gas  into  the  condenser  we  increase  the 
amount  three  times,  or  to  225  volumes,  the 
increased  delivery  from  the  condenser  (by 
means  of  the  expansion  valves)  of  only  two 
volumes  is  insignificant  in  comparison  with 
the  increased  receipt  from  the  compressor, 
and  therefore  the  increase  of  excess  con- 
densing pressure  is  what  might  naturally  be 
expected  to  accompany  increased  suction 
pressure, 


62  Theoretical  and  Practical 

OTHER  CONDITIONS  THAT  AFFECT 
EXCESS  PRESSURE. 

No  table  of  the  excess  condensing  pres- 
sures for  various  suction  pressures  would  be 
of  any  practical  use,  because  different  makes 
of  refrigerating  plants  give  different  results. 
The  high  speed  (140  revolutions  per  min- 
ute) horizontal  compressor  invariably  gives 
a  greater  excess  pressure  than  the  vertical 
compressor,  which  only  has  a  speed  of 
from  40  to  60  revolutions  per  minute.  The 
method  of  connecting  the  condenser  piping 
also  affects  the  excess  pressure  considera- 
bly, and  if  four  separate  one-inch  pipes,  or 
worms,  connected  by  manifolds  are  used,  the 
excess  pressure  will  be  greater  than  if  one 
continuous  worm  (starting  at  the  top  with 
two-inch  piping  and  reducing  to  one-inch, 
as  recommended  in  previous  pages)  is  used. 
Also,  the  higher  the  condensing  pressure 
due  to  the  temperature  of  the  condensing 
water  the  greater  the  excess  pressure  will 
be. 


Ammonia  Refrigeration.  63 

USE   OF   CONDENSING   PRESSURE   IN  DE- 
TERMINING Loss  OF  AMMONIA 
BY  LEAKAGE. 

As  the  condensing  pressure  is  one  of  the 
principal  means  by  which  the  engineer  can 
tell  when  the  loss  of  ammonia  by  leakage  has 
amounted  to  such  a  quantity  as  to  render  the 
replenishing  of  the  plant  advisable,  it  is  very 
necessary  that  the  man  in  charge,  if  inexpe- 
rienced, should  record  in  a  book  the  temper- 
ature of  the  condensed  ammonia  at  its  point 
of  exit  from  the  condenser,  and  the  suction 
and  condensing  pressures,  every  two  or  three 
hours.  If  these  figures  are  thoroughly  mem- 
orized and  the  engineer  started  with  a  plant 
that  was  fully  charged  with  ammonia  he 
ought  to  be  able,  at  the  end  of  a  month  or 
two,  to  tell  by  looking  at  the  suction-pres- 
sure gauge,  and  the  temperature  of  the  con- 
densed ammonia  whether  the  condensing 
pressure  was  what  it  should  be.  For  ex- 
ample, suppose  the  plant  has  been  running 
for  two  or  three  months  with  an  average 
condensing  temperature  of  60°  Fahr.,  con- 


64  Theoretical  and  Practical 

densing  pressure  of  120  Ibs.  and  suction 
pressure  of  25  Ibs.,  and  that  during  the 
next  three  months  the  condensing  pressure 
gradually  fell  to  1 1  5  Ibs.,  while  the  condens- 
ing temperature  and  suction  pressure  were 
still  60°  Fahr.  and  25  Ibs.  respectively;  it 
would  be  plain  that  neither  the  condensing 
temperature  nor  the  suction  pressure  could 
account  for  this  falling  off  in  the  condensing 
pressure  because  they  have  not  altered,  and 
therefore  it  is  obvious  that  the  quantity  of 
ammonia  can  alone  account  for  this  altera- 
tion. The  diminution  in  the  condensing 
pressure  caused  by  loss  or  leakage  of  am- 
monia is  due  to  the  increased  condenser 
space  resulting  from  the  leakage,  thereby 
allowing  the  gas  a  greater  length  of  worm 
in  which  to  condense  and  assume  the  liquid 
form,  thus  lessening  the  "crowding"  of  the 
hot  compressed  gas. 

When  the  condensing  pressure  falls  off  5 
or  10  Ibs.  the  plant  should  be  re-charged 
with  sufficient  ammonia  to  restore  the  nor- 
mal condensing  pressure. 


Ammonia  Refrigeration.  65 

COOLING  DIRECTLY  BY  AMMONIA. 

It  is  very  seldom  that  ammonia  can  be 
used  directly  for  freezing  purposes,  and  in 
nearly  all  cases  it  is  used  indirectly  with 
brine  as  a  medium.  The  greatest  drawback 
to  using  ammonia  directly  is  the  liability  of 
ammonia  to  leak  through  the  fittings,  joints, 
etc.,  and  as  meats  or  other  provisions  would 
be  rendered  valueless  as  far  as  the  market  is 
concerned  by  such  a  leakage,  it  would  be 
exceedingly  risky  and  injudicious  to  cool  a 
warehouse  directly  by  ammonia  if  the  only 
object  for  so  doing  was  to  save  the  cost  of 
the  brine  portion  of  the  plant.  But  in  build- 
ings where  a  slight  smell  of  ammonia  would 
not  result  in  any  pecuniary  loss — other  than 
the  value  of  the  escaping  ammonia,  which 
latter  if  properly  looked  after  will  be  ex- 
ceedingly small — it  would  certainly  be  advis- 
able to  cool  directly  by  ammonia.  In  this 
case  the  expansion  valves  would  be  in  the 
building  to  be  cooled,  and  the  ammonia 
would  be  expanded  in  a  system  of  piping 
hung  up  on  the  walls  or  otherwise  conve- 


66  Theoretical  and  Practical 

niently  arranged.  This  method  of  working 
is  decidedly  the  most  economical,  as  it  does 
away  with  the  necessity  of  a  refrigerator  and 
its  long  series  of  piping,  the  brine  pumps  and 
the  steam  required  to  run  them,  the  brine 
piping  (4  to  5  inches  in  diameter)  conveying 
the  brine  between  the  pumps,  building  to  be 
cooled,  and  the  refrigerator,  and  all  the 
numerous  fittings  and  valves  in  connection 
therewith. 

BRINE. 

Brine  is  a  solution  of  either  common  salt 
(chloride  of  sodium),  chloride  of  calcium,  or 
chloride  of  magnesium  in  water.  Brine  made 
of  chloride  of  magnesium  is  undesirable,  as 
it  is  liable  to  contain  free  acid,  which  above 
all  other  things  is  most  objectionable,  owing 
to  its  action  on  metals  ;  whereas  common  salt, 
or  the  "commercial  fused"  chloride  of  cal- 
cium, are  both  free  from  acid.  Salt  is  usually 
sold  by  the  bag,  each  bag  containing  about 
200  Ibs.  and  costing  about  7<Dc.,  or  $7.00  per 
ton.  Commercial  fused  chloride  of  calcium 


Ammonia  Refrigeration.  67 

is  sold  in  iron  drums,  holding  about  600  Ibs. 
each,  and  costs  about  $16.00  per  ton.  Cheap 
common  salt,  such  as  may  be  obtained  for  40 
to  50  cents  per  bag,  should  not  be  used,  as  it 
will  be  expensive  in  the  long  run,  and  noth- 
ing but  the  purest  and  best  salt  should  be 
bought.  Common  salt  for  brine  making 
should  not  contain  more  than  0.05  per  cent, 
of  insoluble  matter  (calculated  on  the  dry 
salt).  The  percentage  of  moisture  is  only 
of  account  when  the  salt  is  bought  by  weight 
instead  of  by  the  bag,  but  the  percentage  of 
insoluble  matter  is  always  of  great  impor- 
tance, because,  unless  there  are  special  facil- 
ities for  filtering  the  brine  before  it  enters 
the  refrigerator  or  system  of  piping  for  cool- 
ing rooms,  etc.,  it  is  obvious  that  if  the  per- 
centage of  insoluble  matter  is  bulky,  it  will 
accumulate  and  eventually  settle  down  in 
the  bottom  of  the  refrigerator  and  thereby 
reduce  the  efficiency  of  the  apparatus  by 
covering  the  piping,  or  it  is  liable  to  pass 
into  the  brine  pumps,  and  from  thence  to 
the  brine  piping  for  cooling  the  rooms,  where 
it  is  likely  to  lodge  in  fittings  (return  bends, 


68  Theoretical  and  Practical 

elbows,  etc.)  and  cause  serious  obstruction. 
The  use  of  chloride  of  calcium  does  not  do 
away  with  the  inconvenience  liable  to  be 
caused  by  the  presence  of  insoluble  matter, 
but  for  temperatures  below  —  7°  Fahr.  it  is 
absolutely  necessary  that  it  should  be  used 
for  the  reason  explained  in  paragraph  on 
"  Effect  of  Composition  on  Freezing  Point." 

FREEZING  POINT  OF  BRINE. 

Brines  will  only  stand  a  certain  degree  of 
cold  without  freezing,  and  the  temperature 
to  which  brine  can  be  cooled  before  it  will 
begin  to  freeze  depends,  firstly,  on  the  com- 
position of  the  brine,  and  secondly,  on  the 

strength  of  the  solution. 

. 

EFFECT   OF   COMPOSITION    ON   FREEZING 
POINT. 

In  illustration  of  the  effect  that  a  change 
in  the  composition  of  the  brine  will  have  on 
the  freezing  point  it  is  only  necessary  to  state 
that  whereas  a  solution  of  common  salt  can 


Ammonia  Refrigeration.  69 

only  be  cooled  to  —  7°  Fahr.,  a  solution  of 
chloride  of  calcium  can  be  cooled  to  —  40° 
Fahr. 


EFFECT  OF  STRENGTH  ON  FREEZING 
POINT. 

In  explaining  the  way  in  which  the 
strength  affects  the  freezing  point  of  the 
solution  a  brine  made  of  common  salt  will 
be  considered.  If  a  weak  solution  of  com- 
mon salt  in  water  is  gradually  cooled,  ice 
will  begin  to  separate  out  at  about  28°  Fahr., 
and  this  separation  of  ice  with  a  proportional 
concentration  of  the  brine  will  continue  till 
the  temperature  of —  7.5°  Fahr.  is  reached. 
At  this  point  the  brine  will  contain  24.24  per 
cent,  of  salt,  and  if  further  cooled  will  solidify 
as  a  whole.  If,  on  the  other  hand,  a  satu- 
rated solution  (at  60°  Fahr.)  of  salt  is  cooled, 
salt  will  separate  out,  and  the  brine  will 
weaken  until  the  same  temperature  and  de- 
gree of  concentration  given  above  is  reached, 
when  the  solution  will  become  wholly  solidi- 
fied. 


70  Theoretical  and  Practical 

SUITABLENESS  OF  THE  BRINE. 

For  all  ordinary  purposes,  such  as  ice 
manufacture,  etc.,  where  it  is  highly  improb- 
able that  a  temperature  below  —  7°  Fahr. 
will  be  needed,  the  author  would  strongly 
advise  the  use  of  a  brine  made  of  common 
salt.  The  cost  is  less  than  one-half  of  that 
of  chloride  of  calcium,  and  it  is  far  easier 
and  more  cleanly  to  handle,  because  chloride 
of  calcium  is  highly  deliquescent,  and  there- 
fore a  drum  of  it  must  be  used  as  soon  as 
opened,  otherwise  it  will  absorb  so  much 
moisture  from  the  air  that  it  will  "run"  and 
cause  much  annoyance — not  to  mention  loss. 
As  we  have  already  seen,  if  the  brine  is 
either  too  weak  or  too  strong,  a  separation 
will  take  place  —  in  the  former  case  of  ice, 
and  in  the  latter  case  of  the  chemical  con- 
stituent. Now,  if  either  of  these  separations 
occurs  it  will  seriously  affect  the  refriger- 
ating efficiency  of  a  plant,  owing  to  the  coat- 
ing of  the  refrigerator  coils  or  piping  with 
a  bad  conducting  material  such  as  ice,  salt, 
or  chloride  of  calcium.  It  is  therefore  of 


Ammonia  Refrigeration.  71 

the  greatest  importance  that  the  gravity  or 
strength  of  the  brine  should  be  carefully  tried 
every  day,  and  any  variation  due  to  evapo- 
ration or  other  causes  should  be  corrected  at 
once. 

MAKING  BRINE. 

The  brine  should  be  made  in  a  separate 
vessel  and  not  be  transferred  to  the  refriger- 
ator until  its  strength  has  been  carefully 
adjusted  and  the  dirt,  etc.,  allowed  sufficient 
time  to  settle  to  the  bottom.  If  the  brine  is 
to  be  made  from  salt,  the  water  is  first  placed 
in  the  vessel  and  carefully  measured,  and  then 
the  requisite  quantity  of  salt — namely,  266.81 
Ibs.*  per  100  gallons  of  water — is  thrown  in 
and  the  whole  stirred  either  mechanically  or 
manually  until  the  salt  is  dissolved.  The 
strength  of  the  brine  should  then  be  22° 
Beaume.  In  the  case  of  chloride  of  calcium 
the  strength  can  not  be  regulated  to  such  a 
nicety  as  in  the  case  of  salt,  because  the 


*  These  figures  are  for  pure,  dry  salt,  and  therefore  the  percentage 
ot  moisture  and  insoluble  matter  contained  in  the  salt  used  must  be 
determined  and  allowed  for. 


^2  Theoretical  and  Practical 

material  has  to  be  placed  in  the  vessel  in 
more  or  less  large  lumps,  and  as  these  lumps 
dissolve  comparatively  slowly  at  the  ordinary 
temperature  it  is  necessary  to  boil  the  water 
with  open  steam.  This  operation,  of  course, 
increases  the  volume  of  the  water  first  placed 
in  the  vessel,  and  as  this  increase  fs  an  un- 
certain quantity  (according  to  the  size  of  the 
lumps  and  therefore  the  length  of  time  they 
take  to  dissolve)  the  strength  has  to  be  regu- 
lated entirely  by  the  use  of  the  hydrometer. 
It  is  wiser  to  make  the  solution  too  strong 
rather  than  too  weak,  as  it  takes  less  time  to 
reduce  the  strength  by  adding  water  than  it 
does  to  increase  the  strength  by  dissolving 
more  of  the  chloride  of  calcium. 


CHAPTER    VII. 

IT  is  advisable  to  place  only  6  gallons  of 
water  for  every  100  Ibs.  of  chloride  of  cal- 
cium in  the  vessel  to  start  with,  and  as  soon 
as  the  solution  is  effected  cold  water  should 


Ammonia  Refrigeration.  73 

be  added,  small  quantities  at  a  time,  until  the 
strength  is  reduced  to  20°  Beaume. 


SPECIFIC  HEAT  OF  BRINE. 

According  to  Professor  Denton,*  the  spe- 
cific heat  of  brine  made  from  common  salt  is 
as  follows  : 

Strength.  Specific  Heat. 

20%°  Beaume  0.818 

2\y2°      "  0.786 

The  author  finds  that  the  specific  heat  of 
brine  of  22°  Beaume  strength  and  made  from 
American  salt  is  0.765. 

REGULATION  OF  BRINE  TEMPERATURE. 

In  places  where  the  refrigerating  work  is 
regular  and  the  temperature  of  the  brine  re- 
turning to  the  refrigerator  is  not  liable  to 
vary  many  degrees,  the  regulation  of  the 
temperature  of  the  outgoing  brine  is  an  easy 
matter ;  but  where  the  return  brine  is  sub- 


*  Transactions  of  the  American  Society  of  Mechanical    Engineers, 
Vol.    XII.,    page  384. 


74  Theoretical  and  Practical 

jected  to  large  variations  in  temperature  the 
regulation  of  the  outgoing  brine  temperature 
requires  a  great  deal  of  attention.  In  the 
former  case  the  expansion  valves  are  regu- 
lated so  that  the  engine  maintains  a  suction 
pressure  equivalent  to  a  boiling-point  (of  the 
anhydrous  ammonia)  of  about  i5°Fahr.  lower 
than  the  brine  temperature  required.  For 
instance,  in  ice-making  a  brine  temperature 
of  25°  Fahr.  would  be  the  most  economical, 
and  1 5°  lower  than  that,  namely,  10°  Fahr., 
would  be  the  temperature  at  which  the  am- 
monia should  boil.  By  referring  to  Table 
III.  (page  116)  it  will  be  seen  that  a  suction- 
gauge  pressure  of  23.85  Ibs.  is  equivalent  to 
an  ammonia  boiling-point  of  10°  Fahr.,  and 
therefore  the  expansion  valves  would  need 
to  be  regulated  so  that  the  engine  ran  with 
a  suction-gauge  pressure  of,  say,  23^  Ibs. 
If  a  building  has  to  be  cooled  and  maintained 
at  a  temperature  of  zero,  a  brine  temperature 
of  about  —  10°  Fahr.  will  be  necessary,  and 
15°  lower  than  that  (=  —  25°  Fahr.)  will  be 
the  required  boiling-point  of  the  ammonia, 
and  Table  III.  shows  that  a  suction-gauge 


Ammonia  Refrigeration.  7$ 

pressure  of  1.47  Ibs.  corresponds  to  that 
boiling-point.  In  both  these  cases  the  ex- 
pansion valves  will  need  little  or  no  attention 
after  they  have  once  been  properly  regu- 
lated ;  but  it  will  now  be  shown  that  if  we 
have  a  quantity  of  hot  oil  that  has  to  be 
cooled  a  certain  number  of  degrees  Fahren- 
heit in  a  given  length  of  time,  it  is  necessary 
that  the  expansion  valves  shall  be  frequently 
attended  to  in  order  to  obtain  the  desired 
results.  For  example  : 

50,000  Ibs.   of  oil  at  a  temperature  of 
iooc  Fahr.  have  to  be  cooled  to 

20°  Fahr.   or  through 

80    Fahrenheit  degrees  in 

24  hours,  and  the  specific  heat  of  the  oil  is 
0.750. 

In  this  case  the  number  of  thermal  units  to 
be  extracted  from  the  oil  are  (50,000  X  80  X 
0.750)  3,000,000.  Now,  if  the  compressor 
is  capable  of  circulating  43,200  cubic  feet 
of  ammonia  gas  per  24  hours,  and  the  ex- 
pansion valves  are  regulated  to  give,  at  the 
commencement,  a  brine  temperature  of  15° 
Fahr.,  the  refrigerating  efficiency  will  be  only 
2,497,000  thermal  units  per  24  hours,  and  it 


76  Theoretical  and  Practical 

will  therefore  take  about  29^  hours  to  cool 
the  oil  to  20°  Fahr.  But  if  the  expansion 
valves  are  regulated  so  that  for  the  first  six 
hours  the  brine  temperature  will  be  32°  Fahr. 
and  during  the  next  12  hours  25°  Fahr.,  and 
the  remaining  six  hours  15°  Fahr.,  the  re- 
frigerating efficiency  will  be,  approximately  : 

First    6    hours  —      882,000  Thermal  units. 
Next  12      "       —  1,542,000         "  " 

Last     6       "      —      624,000         "  " 


Total,  3,048,000  Thermal  units, 


or  48,000  thermal  units  more  than  are  theo- 
retically required,  and  551,000  thermal  units 
more  than  could  be  extracted  by  starting 
with,  and  maintaining  for  24  hours,  the  re- 
quired final  brine  temperature  of  15°  Fahr. 
This  great  difference  in  the  results  r,  due  to 
the  simple  fact  that  the  refrigerating  efficiency 
of  a  plant  is  proportional  to  the  weight  of 
anhydrous  ammonia  circulated,  and  therefore 
if  a  large  weight  of  ammonia  is  circulated  at 
the  commencement,  when  the  temperature  of 
the  oil  is  high,  and  that  weight  is  gradually 
reduced  as  the  oil  becomes  cooled,  it  is  evi- 


'TJHJVHRSITY; 

Ammonia  Rcfrigcrd^^ttlf^S^ 

^^ss—ss^1^ 

dent  that  the  oil  will  be  cooled  quicker  than 
if  the  smaller  weight,  or  that  necessary  for 
the  final  temperature,  is  circulated  through- 
out the  whole  of  the  operation.  Of  course, 
it  would  not  be  advisable  to  regulate  the  ex- 
pansion valves  so  as  to  cause  the  three  sud- 
den drops  in  temperature  as  in  the  above 
example — where  it  was  done  for  simplicity's 
sake — but  the  valves  should  rather  be  gradu- 
ally closed,  so  that  the  minimum  brine  tem- 
perature required  will  be  reached  about  six 
hours  before  the  material  that  is  being  cooled 
will  be  required. 

INDIRECT  EFFECT  OF  CONDENSING  WATER 
ON  BRINE  TEMPERATURE. 

If  the  supply  and  temperature  of  the  water 
used  in  the  condenser  is  irregular  the  expan- 
sion valves  will  need  constant  attention  (no 
matter  what  the  nature  of  the  refrigerating 
work  may  be),  because  any  irregularities  in 
the  condensing  water  will  cause  changes  in 
the  condensing  pressure.  If  the  supply  les- 
sens in  quantity  the  temperature  of  the  con- 


78  TJicorctical  and  Practical 

denser  will,  of  course,  rise  and  cause  an 
increase  of  pressure.  The  natural  result  of 
increased  pressure  will  be  a  larger  delivery 
of  ammonia  forced  through  the  expansion 
valves,  and  the  suction  pressure  will  in  turn 
also  be  increased.  It  is  therefore  necessary 
to  counterbalance  increase  of  condensing 
pressure  by  a  proportional  closing  down  of 
the  expansion  valves,  and  decrease  in  the 
condensing  pressure  by  opening  the  expan- 
sion valves. 


CHAPTER  VIII. 

DIRECTIONS     FOR     DETERMINING     REFRIG- 
ERATING   EFFICIENCY. 

BEFORE  going  into  the  details  of  deter- 
mining the  efficiency  of  a  refrigerating  plant 
it  is  necessary  that  one  or  two  points  in  con- 
nection therewith  should  be  explained. 


Ammonia  Refrigeration.  79 

EQUIVALENT  OF  A  TON  OF  ICE. 

The  equivalent  of  a  ton  of  ice  is  284,000 
British  thermal  units,  or  the  amount  of  heat 
that  would  be  necessary  to  convert  a  ton 
(2,000  Ibs.)  of  ice  at  32°  Fahr.,  into  a  ton 
of  water  at  32°  Fahr.,  or,  conversely,  it  is  the 
amount  of  heat  that  must  be  extracted  from 
a  ton  of  water  at  32°  Fahr.  in  order  to  con- 
vert it  into  a  ton  of  ice  at  32°  Fahr. 


COMPRESSOR  MEASUREMENT  OF  AMMONIA 
CIRCULATED. 

Professor  Denton's  determinations  *  show 
that  when  the  ammonia  gas  enters  the  com- 
pressor it  is  heated  by  the  walls  of  the  latter 
md  so  rarefied  as  to  cause  the  compressor 
full  of  gas  to  weigh  upwards  of  25  per  cent, 
less  than  it  would  if  the  gas  remained  at  the 
temperature  of  the  entrance  while  the  com- 
pressor filled. 


*  Transactions   of  the  American  Society  of  Mechanical   Engineers, 
Vol.  XII. 


8o  Theoretical  and  Practical 

Loss   IN  WELL-JACKETED  COMPRESSORS. 

The  make  of  machine  with  which  Denton 
experimented  was  the  Consolidated  Ice  Ma- 
chine Company's,  and  the  actual  loss  in  the 
pumping  efficiency  of  the  compressors  due 
to  the  above  cause  was  2 1.4  per  cent.  The 
compressors  (including  gas  passages,  valves, 
etc.)  in  this  make  of  machine  are  exception- 
ally well  arranged  for  receiving  the  fullest 
possible  benefit  from  the  jacket-water,  and 
therefore  the  loss  of  pumping  efficiency  is 
reduced  to  a  minimum.  Where  compressors 
are  not  so  efficiently  jacketed,  the  loss  by 
superheating  will  vary  from  2\y2  to  25  per 
cent. 

LOSS     IN     DOUBLE-ACTING    COMPRESSORS. 

An  allowance  of  30  per  cent,  for  loss  by 
superheating  is  necessary  in  the  case  of 
double-acting  compressors  when  the  gas  en- 
ters the  compressor  through  the  heads  and 
the  heads  are  not  jacketed. 

Before  the  efficiency  of  a  plant  can  be  de- 
termined it  is  necessary  that  the  compressor 


Aim  no  nia  Refrigeration.  8 1 

should  be  fitted  with  an  indicator,  the  engine 
and  brine  pumps  with  stroke  counters,  and 
that  mercury  wells  should  be  placed  at  the 
following  points,  viz. : — 


DISTRIBUTION  OF  MERCURY  WELLS. 

(1)  On  the  discharge  pipe,  near  its  point 
of  outlet  from  the  compressor. 

(2)  On  the  ammonia  discharge  pipe  from 
the  condenser — immediately  at  its  point  of 
exit. 

(3)  In  the  ammonia  supply  manifold  of  the 
refrigerator. 

(4)  In  the  ammonia  suction — or  discharge 
— manifold  of  the  refrigerator. 

(5)  In  the  ammonia  suction  pipe  —  imme- 
diately  at    its    point    of  entry   to    the    com- 
pressor. 

(6)  In  the  return  brine  pipe,  just  where  it 
discharges  into  the  refrigerator. 

(7)  In  the  brine  discharge  brine  pipe  from 
the  refrigerator. 

In    cases   where   the   pipes    are   horizontal 
and  of  sufficient  diameter  the  mercury  well 


82  Theoretical  and  Practical 

should  be  constructed  as  in  Fig.  9,  in  which 
A  is  the  pipe,  the  temperature  of  the  con- 


Fig.  IX 


tents  of  which  is  required ;   B  is  the  mercury 
well,  made  of  iron  tubing  and  fitted  in  the 


Ammonia  Refrigeration.  83 

pipe  by  means  of  a  bushing.      The  mercury, 

C,  fills    the    well    about    three-quarters    full, 
and   in    it   the    thermometer,   D,   is   held    by 
the  cork,   K. 

When  the  pipes  are  vertical,  or  of  too 
small  a  diameter,  the  mercury  well  should 
be  made  as  follows  (Fig.  10): — 

The  wooden  block,  B,  having  a  cavity,  C, 
is  carefully  fitted  to  the  pipe,  A,  and  se- 
curely fastened  in  its  place  by  the  iron  bands 

D,  D.       C   is   filled   three-quarters   full   with 
mercury,    and    the    thermometer,    E,    having 
been  introduced  and  secured  in  its  place  by 
the  cork,  F,  the  whole  is  so  wrapped  in  hair- 
felt  as  to  entirely  prevent  any  possibility  of 
the   atmosphere  having  any  effect  upon  the 
temperature  of  the  mercury. 

The  portion  of  the  pipe  with  which  the 
mercury  comes  in  contact  should  be  thor- 
oughly scraped,  so  as  to  present  a  perfectly 
bright  and  clear  surface,  before  the  wooden- 
block  is  fastened  in  its  place. 

The  judicious  application  of  a  little  soft 
putty  to  touching  surface  of  the  wood  will 


84 


Theoretical  and  Practical 


make  the  joint  between  the  wood  and  pipe 
perfectly  tight  and  efficient. 


Fig.  1O. 


The    most   convenient   form   of    thermom- 
eter is  one  with  a  cylindrical    bulb    78   to    \ 


Ammonia  Refrigeration.  85 

inch  long  ;  the  diameter  of  the  thermometer 
should  be  about  5-16  to  $6  of  an  inch.  The 
graduations  should  start  at  a  point  3  inches 
above  the  top  of  the  bulb  and  should  be 


Plan  Thro'  XY 


y&  of  an  inch  apart,  and  each  graduation 
should  represent  one  degree.  With  the  use 
of  such  a  thermometer  a  reading  of  one- 
tenth  of  a  degree  may  be  easily  and  accu- 
rately made. 


86  Theoretical  and  Practical 

EXAMINATION  OF  WORKING  PARTS. 

Having  carefully  examined  the  pistons  and 
valves  of  the  brine  pumps  and  compressor, 
and  verified  the  accuracy  of  the  pressure 
gauges,  a  number  of  tabulated  forms  should 
be  drawn  up  ready  to  receive  the  readings 
of  the  different  instruments  as  they  are 
taken. 

NUMBER  OF  READINGS  TO  BE  TAKEN. 

Where  a  plant  is  doing  "  steady  tempera- 
ture" work,  such  as  cooling  warehouses  or 
making  artificial  ice,  readings  of  all  the  dif- 
ferent  instruments  need  not  be  taken  more 
than  once  every  half-hour ;  but  where  the 
range  in  temperature  of  the  material  to  be 
cooled  is .  large,  readings  should  be  taken 
every  quarter  of  an  hour.  Diagrams  of  the 
steam  cylinder  and  the  compressor  should 
be  taken  every  three  hours. 


Ammonia  Refrigeration.  87 

CHAPTER    IX. 

DURATION     OF    TEST. 

FOR  steady  work,  the  test  should  last  for 
twelve  hours,  and  in  large  range  of  tempera- 
ture work  the  test  should  last  for  twenty-four 
hours,  or,  at  any  rate,  until  the  final  temper- 
atures agree  as  closely  as  possible  with  those 
at  the  start. 

INDICATOR  DIAGRAMS. 

In  order  to  check  the  brine  figures  a  very 
careful  examination  of  the  indicator  diagrams 
of  the  compressor  must  be  made,  as  it  is  only 
by  the  aid  of  these  diagrams  that  an  accurate 
computation  of  the  volume  of  ammonia  cir- 
culated can  be  made. 

Fig.  1 1  represents  the  working  of  a  double- 
acting  horizontal  compressor  running  at  140 
revolutions  per  minute.  The  gauge  pressure 
in  the  suction  discharge  pipes  of  the  com- 


88  Theoretical  and  Practical 

pressor  when  the  diagram  was  taken  were, 
respectively,  10  Ibs.  and  140  Ibs.  As  the 
diagram  shows  that  the  suction  pressure  in 
the  compressor  was  only  5  Ibs.  ar.d  the  con- 
densing pressure  was  150  Ibs.,  it  is  very  evi- 
dent, in  the  first  place,  that  both  the  suction 
and  discharge  valves  were  too  small  and  did 


CONDENSING 140 

SUCTION 10 

REVOLUTIONS    PER    MINUTE  -   140 


GAUGE    PRESSURES 


ATMOSPHERIC    LINE 

FIG.  XI. 


not  admit  of  the  free  passage  of  the  ammo- 
nia gas.  Secondly,"  as  the  suction  pressure 
in  the  compressor  was  only  5  Ibs.  the  com- 
pressor was  not  pumping  or  circulating  as 
much  ammonia  as  the  gauge  pressure  repre- 
sented. This  diagram  also  shows  that  the 
engine  had  performed  30  per  cent  of  its  for- 


A  mmonia  Refrigeration. 


ward  stroke  and  25  per  cent,  of  its  return 
stroke  before  the  pressure  due  to  the  re- 
expansion  of  the  clearance  space  gas  was 
reduced  to  the  suction  pressure  —  the  pres- 
sure at  which  the  valves  would  open.  In 
this  case  the  pumping  capacity  of  the 
compressor  was,  therefore,  only  72^3  Per 


[CONDENSING  —  -137 

(SUCTION 10 

REVOLUTIONS    PER    MINUTE  -  140 


GAUGE    PRESSURES 


MMOSPHERIC    LINE 

FIG.  XII. 


cent,  of  the  piston  displacement  per  revolu- 
tion. 

Fig.  1 2  represents  the  working  of  the  same 
engine  after  the  discharge  valves  had  been 
enlarged.  Although  the  engine  was  running 
at  the  same  speed  as  before — 140  revolutions 
per  minute — the  condensing  pressure  in  the 


90  Theoretical  and  Practical 

compressor  was  this  time  the  same  as  indi- 
cated by  the  gauge  on  the  discharge  pipe, 
showing  that  the  engine  had  no  "excess" 
pressure  to  work  against,  and  therefore  a 
saving  in  steam  was  effected.  The  diagram 
again  shows,  however,  that  the  suction  valves 
were  too  small  for  a  speed  of  140  revolu- 


PRESSURE8J— — 
REVOLUTIONS    PER    MINUTE  -  120 


ATMOSPHERIC    LINE 

FIG.  XIII. 


tions  per  minute,  and,  also,  that  the  pumping 
capacity  of  the  compressor  was  only  72^ 
per  cent,  of  the  piston  displacement 

Fig.  1 3  is  the  diagram  taken  from  the  same 
engine  when  running  at  the  rate  of  only  1 20 
revolutions  per  minute.  From  it  we  see  that 
the  suction  valves  of  the  compressor  are  de- 


Ammonia  Refrigeration.  91 

signed  for  that  rate  of  speed,  and  that  the 
previous  rates  of  140  revolutions  per  minute 
were  beyond  the  capacity  of  the  valves. 

Fig.  14  was  a  diagram  taken  from  a  com- 
pound- single-acting  vertical  compressor  run- 
ning at  40  revolutions  per  minute,  with  a 
suction  and  condensing  gauge  pressure  of, 


GAUGE   PRESSURES 

REVOLUTIONS    PER    MINUTE  -     40 


100 

\ 

hv= 

= 

_50_ 
0 

ATMO 

F 

5PHERI 
IG.  X 

;  LINE 
IV. 

^  — 

respectively,  10  Ibs.  and  137  Ibs.  This  dia- 
gram exhibits  an  almost  perfectly  square  heel, 
the  loss  being  only  I  per  cent,  of  the  piston 
displacement,  and  shows  that  the  suction  and 
discharge  valves  were  of  requisite  size. 

We  will  now  see  what  these  diagrams  ac- 
tually represent  in  pounds  of  ammonia  cir- 


92  TJicorctical  and  Practical 

dilated  per  24  hours,  and  from  those  figures 
we  will -be  better  able  to  realize  the  impor- 
tance of  this  portion  of  the  subject. 

For  simplicity's  sake  we  will  suppose  the 
temperature  of  the  gas  entering  the  •  com- 
pressor was  o°  Fahr.  in  all  four  cases.  The 
cubical  displacement  of  the  piston  in  the  case 
of  the  horizontal  compressor  was  1.30  cubic 
feet  per  revolution,  and  in  the  case  of  ver- 
tical compressor  4.00  cubic  feet  per  revolu- 
tion. 

140  revolutions  per  minute  X  1.3  =  182 
cubic  feet  per  minute  =  262,080  cubic  feet 
per  24  hours. 

-The  indicator  diagram  shows  that  27.5 
per  cent,  of  this  was  lost  owing  to  re-ex- 
pansion of  the  gas,  and  we  have  seen  under 
sub-heading  "  Loss  in  Double-acting  Com- 
pressors," that  30  per  cent,  also  has,  in  this 
case,  to  be  deducted,  and  therefore  the  ef- 
fectual displacement  is  (  (262,080  —  27.5  per 
cent.)  —  30  per  cent.)  =  133,005  cubic  feet 
per  24  hours. 

The  suction  pressure  in  the  compressor 
was  5  Ibs.  (i.e. ,  19.7,  say,  19^  Ibs.  absolute 


Ammonia  Refrigeration.  93 

pressure).  By  Table  V.  (page  125)  we  see 
that  i  Ib.  of  ammonia  gas  at  o°  Fahr.  and 
19^  Ibs.  absolute  pressure  =  14.828  cubic 
feet ;  therefore  the  effectual  displacement  of 
133,005  cubic  feet  =  8,970  Ibs.  of  ammonia 
circulated  per  24  hours. 

1 20  revolutions  per  minute  X  1.3  =  156 
cubic  feet  per  minute  =  224,640  cubic  feet 
per  24  hours. 

Taking  72.5  per  cent,  of  this  amount,  and 
then  deducting  30  per  cent,  of  the  remainder, 
we  have  an  efficiency  of  114,004  cubic  feet 
per  24  hours. 

The  suction  pressure  in  the  compressor 
was  10  Ibs.  (=  24^  Ibs.  absolute  pressure). 
By  Table  V.  (page  127)  we  see  that  I  Ib. 
of  ammonia  gas  at  o°  Fahr.  and  24^  Ibs. 
absolute  pressure  =  1 1.794  cubic  feet ;  there- 
fore the  effectual  displacement  of  114,004 
cubic  feet  =  9,666  Ibs.  of  ammonia  circulated 
per  24  hours. 

In  the  cases  of  diagrams  1 1  and  12,  where 
the  engine  was  running  at  a  speed  of  140 
revolutions  per  minute,  the  pounds  of  am- 
monia circulated  were  only  8,970  as  against 


94  Theoretical  and  Practical 

9,666  when  the  engine  speed  was  only  120 
revolutions  per  minute.  This  increase  of 
696  Ibs.  in  the  circulation  of  ammonia  per  24 
hours,  together  with  the  smaller  consump- 
tion of  steam  (owing  to  the  diminution  in  the 
speed  of  the  engine)  is  due  entirely  to  suffi- 
cient time  being  allowed  the  ammonia  gas 
in  its  passage  through  the  suction  valves  to 
maintain  its  suction  pressure  of  10  Ibs.,  at 
which  pressure  I  Ib.  of  ammonia  gas  only 
occupies  11.794  cubic  feet.  If  the  piston 
traveled  quicker  than  the  above  speed  it 
sucked  the  gas  instead  of  allowing  it  to 
follow  by  its  own  pressure,  and  thereby 
reduced  the  pressure  to  (in  the  cases  of  dia- 
grams ii  and  12)  5  Ibs.,  at  which  pressure 
i  Ib.  of  ammonia  gas  occupies  14.828  cubic 
feet,  and  the  pumping  capacity  of  the  com- 
pressor, as  far  as  the  weight  of  ammonia  cir- 
culated is  concerned,  is  thereby  reduced. 

40  revolutions  per  minute  X  4  =  160  cubic 
feet  per  minute  =  230,400  cubic  feet  per  24 
hours. 

99  per  cent,  of  this  amount  equals  228,096 
cubic  feet,  and,  as  in  the  case  of  a  thoroughly- 


Ammonia  Refrigeration.  95 

jacketed  single-acting  compressor,  21.4  per 
cent,  instead  of  30  per  cent,  has  to  be  de- 
ducted. The  effectual  displacement  in  this 
case  is  179,283  cubic  feet  per  24  hours. 

We  have  already  seen  that  I  Ib.  of  ammo- 
nia gas  at  o°  Fahr.  and  10  Ibs.  (=  24^  Ibs. 
absolute  pressure)  =  11.794  cubic  feet,  and 
therefore  the  available  179,283  cubic  feet 
=  15,201  Ibs.  of  ammonia  circulated  per  24 
hours. 

The  actual  capacity  of  this  vertical  com- 
pressor is  230,400  cubic  feet  per  24  hours  as 
against  224,640  in  the  case  of  the  horizontal 
compressor  when  diagram  1 3  was  taken,  or 
an  excess  of  only  5,760  cubic  feet  per  24 
hours.  Yet  the  increase  in  the  amount  of 
ammonia  circulated  amounted  to  (15,201  — 
9,666)  5,535  Ibs.  of  ammonia  per  24  hours, 
which  figures,  if  allowance  is  made  for  the 
5,760  cubic  feet  excess  capacity,  are  re- 
duced to  5,042  Ibs.  This  enormous  increase 
of  5>°42  Ibs.  in  the  weight  of  ammonia  cir- 
culated is  almost  entirely  due  to  the  fact 
that  the  water-jacket  on  the  compressor 
head  of  the  vertical  compressor  causes  a 


96  Theoretical  and  Practical 

complete  collapse  of  the  clearance  space 
gas,  and  thereby  allows  the  suction- valves 
to  open  immediately  the  piston  commences 
its  return  stroke. 

Having  ascertained  the  circulating  capacity 
of  our  compressor  we  will  now  see  what  the 
freezing  capacity  of  the  plant  is  and  how  it 
could  be  improved. 

We  will  suppose  that  the  mean  results  of  a 
24-hour  test  were  as  follows  : 

Gauge  Pressure   5    SuCti°n IO  lbs- 

(    Discharge  (Condensing)  ....    140  lbs. 

r   Suction    ...   8°  Fahr. 
at  Compressor  <    -p.-     ,  -r-,  , 

Ammonia  <  (    -Discharge     .  251  rahr. 

Temperature    ^     at  Discharge  from  Condenser,  62°  Fahr. 

!at  Refrig'ator  Supply  Manifold,  69°  Fahr. 
"  "  Discharge     "         o°  Fdhr. 

C    Leaving  Refrigerator i6l4°  Fahr. 

1  emperaturcs  •>    -,,  ,     T, 

.  t    Return  to 31^0  j,anr 

Revolutions  of  Pump  per  Minute 40 

Strength 22°  Beaume. 

Revolutions  of  Compressor  Engine  per  Minute 120 

Diagram  1 3  represented  the  working  of  the 
compressor  while  the  test  was  being  made. 
The  compressor  piston  displacement  was  1.30 
cubic  feet  per  revolution. 

The  displacement  of  the  brine  pump  piston 
was  0.802 1  gallon  per  revolution. 


Ammonia  Refrigeration.  97 

AMMONIA  FIGURES.  —  EFFECTUAL  DIS- 
PLACEMENT. 

Compressor:  120  revolutions  per  minute  X 
1.3  =  156  cubic  feet  per  minute  =  224,640 
cubic  feet  per  24  hours.  This  amount  less 
27.5  per  cent.  =  162,864  cubic  feet,  and  30 
per  cent,  deducted  from  that  leaves  114,005 
cubic  feet  effectual  displacement  per  24 
hours. 

VOLUME  OF  GAS. 

The  gas  as  it  entered  the  compressor  was 
at  a  temperature  of  8°  Fahr.  and  under  a 
gauge  pressure  of  10  Ibs.  (=  24.7  Ibs.  abso- 
lute pressure).  By  referring  to  Table  VI.  we 
see  that  I  Ib.  of  ammonia  gas  at  24^  (24.75) 
Ibs.  absolute  pressure  and  8°  Fahr.  =  12.013 
cubic  feet  and  at  24.5  Ibs.  pressure  and  8° 
Fahr.  =  12.137  cubic  feet.  Our  pressure  was 
24.7  Ibs.,  or  0.05  Ibs.  less  than  24^,  so,  as 
there  are  5,  5-100  difference  between  24^ 
and  24^,  we  divide  the  difference  in  the 
volume  of  the  gas  at  those  two  pressures  by 


98  Theoretical  and  Practical 

5  and  add  the  quotient  to  the  figures  due  to 
the  pressure  24.75  Ibs.     Thus  : 

12.137 — 12.013  =  0.124;  0.124-^5  =  0.0248.  12.013-}- 

0.0248  =  12.0378  cubic  feet  =  the  volume  of  I  Ib.  of  am- 
monia gas  at  8°  Fahr.  and  24.7  Ibs.  absolute  pressure. 


AMMONIA  CIRCULATED  PER  TWENTY- 
FOUR  HOURS. 

The  effectual  displacement  of  the  com- 
pressor was  162,864  cubic  feet,  and  as  the 
volume  of  one  pound  of  the  gas  was  12.0378 
cubic  feet,  the  amount  of  ammonia  circu- 
lated per  24  hours  was  (114,005  -r-  12.0378) 
9,470  Ibs. 

REFRIGERATING  EFFICIENCY. 

We  see  by  referring  to  Table  III.  (page 
1 1 6)  that  the  latent  heat  of  ammonia  at 
9.86*  Ibs.  gauge  pressure  is  561,  therefore 
(9,470  X  561  =)  5,312,670  thermal  units  were 
absorbed  by  the  ammonia  in  passing  from 
the  liquid  to  the  gaseous  state  (/.  e.t  in  ex- 

*  For  all  Fractic:il  purposes  these  figures  are  near  enough  to 
10  Ibs. 


Ammonia  Refrigeration.  99 

panding),  but  the  average  results  of  the  test 
show  that  the  ammonia  entered  the  refriger- 
ator at  a  temperature  of  69°  Fahr.  and  that 
the  gas  left  at  a  temperature  of  o°  Fahr. ,  it 
was  therefore  cooled  down  from  69°  to  o°,  or 
through  69  degrees,  and  as  the  specific  heat 
of  ammonia  at  suction  pressures  is  0.508,  as 
already  shown,  it  is  evident  (9,470  X  69  X 
.508)  =  331,942  thermal  units  were  thus  util- 
ized in  cooling  down  the  ammonia  itself, 
and  therefore,  not  being  available  for  cool- 
ing down  the  brine,  they  must  be  deducted 
from  the  5,312,670  thermal  units  credited  to 
the  ammonia,  thus  leaving  (5,312,670  —  331,- 
942  =)  4,980,728  effective  thermal  units,  or 
(4,980,728  -T-  284,800  =)  17.49  tons  of  ice  pei 
24  hours. 

BRINE  FIGURES. —  GALLONS  CIRCULATED. 

The  capacity  of  the  brine  pumps  per  revo- 
lution was  0.8021  gallon,  and  as  it  made  40 
revolutions  per  minute,  the  volume  of  brine 
circulated  wras  0.8021  X  40  X  1440  =  46,200 
rallons*  per  24  hours. 


American  gallons  (=  8.3^  Ibs.  of  water). 


loo  Theoretical  and  Practical 

POUNDS    CIRCULATED. 

The  gravity  of  the  brine  was  22°  Beaume, 
and  as  brine  at  that  strength  weighs  9.84  Ibs. 
per  gallon,  the  number  of  pounds  of  brine 
circulated  in  the  24  hours  was  (46,200  X 
9.84  =)  454,608. 

DEGREES  COOLED. 

The  average  temperatures  of  the  brine 
were  : 

Return       —  31^°  Fahr. 

Outgoing  —  16^°  Fahr.     Therefore  the  brine  was  cooled 

I0  Fahr. 


TOTAL  DEGREES  EXTRACTED. 

The  total  number  of  degrees  Fahrenheit 
that  were  extracted  from  the  brine  were 
(454,608  X  15.25  =)  6,932,772. 


Ammonia  Refrigeration.  IOI 


CHAPTER   X. 

WE  have  shown  previously  that  the  spe- 
cific heat  of  22°  Beaume  brine  is  0.765, 
therefore  the  number  of  thermal  units  ex- 
tracted were  (6,932,772  X  0.705  =)  4,887,604, 
or  (4,887,604-1-284,800)  17.16  tons  of  ice 
per  24  hours.  These  figures  give  0.33  ton 
of  ice  per  24  hours  less  than  we  obtained 
from  the  ammonia  figures.  This  is  a  result 
that  must  always  be  looked  for,  as  no  insula- 
tion is  perfectly  non-conducting,  and  the  air 
surrounding  the  refrigerator,  etc.,  is  always 
cooled  more  or  less  according  to  circum- 
stances. The  heat  imparted  to  the  refrig- 
erator, etc.,  in  this  way  is  a  varying  amount 
and  can  not,  under  ordinary  circumstances, 
be  accurately  estimated.  It  will  have  been 
noticed  in  the  average  ammonia  tempera- 
tures that  the  liquid  anhydrous  ammonia  was 
heated  from  62°  Fahr.  up  to  69°  Fahr.  in  its 
passage  from  the  condenser  to  the  refriger- 
ator supply  manifold.  We  will  now  see  what 


IO2  Theoretical  akd  Practical 

effect   this    rise    in   temperature   had  on  the 
capacity  of  the  plant. 


Loss  DUE   TO  HEATING  OF  LIQUID 
AMMONIA. 

We  have  just  figured  that  5,312,670  ther- 
mal units  were  absorbed  by  the  ammonia 
in  passing  from  the  liquid  to  the  gaseous 
state,  and  that  331,942  thermal  units  of  that 
amount  had  to  be  deducted  for  loss  due  to 
cooling  the  ammonia  itself  from  69°  Fahr.  to 
0°  Fahr. 

.Let  it  now  be  assumed  that  the  tempera- 
ture of  the  liquid  ammonia  remained  at  its 
condensing  temperature  of  62°  Fahr.  and  our 
figures  will  be  :  9,470  (Ibs.  of  ammonia)  X 
62  X. 0.508  =  298,267  thermal  units  required 
to  cool  the  ammonia  itself  from  62°  Fahr.  to 
o°Fahr.,  and  therefore  the  number  of  ther- 
mal units  available  for  cooling  the  brine 
would  be  (5,312,670  —  298,267  =)  5,014,403, 
or  17.61  tons  of  ice  per  24  hours.  These 
figures  show  that  the  seven  degrees  Fahren- 


Ammonia  Refrigeration.  103 

heit  that  the  ammonia  was  heated  in  its  pas- 
sage from  the  condenser  to  the  refrigerator 
represented  a  loss  in  the  refrigerating  effi- 
ciency of  the  plant  of  (17.61  —  17.49  =)  0.12, 
or  one-eighth  of  a  ton  of  ice  per  24  hours. 


Loss  DUE  TO  HEATING  OF  AMMONIA 
GAS. 

A  glance  at  the  average  figures  again  will 
also  show  that  the  ammonia  gas  in  its  pas- 
sage from  the  refrigerator  to  the  compressor 
was  heated  eight  degrees  Fahrenheit — the 
gas  entering  the  compressor  at  a  tempera- 
ture of  8°  instead  of  o°.  To  determine  what 
was  the  lost  refrigerating  effect  in  this  case 
it  will  be  necessary  to  calculate  how  many 
pounds  of  ammonia  would  have  been  circu- 
lated by  the  compressor  had  the  temperature 
of  the  ammonia  gas  remained  at  o°  until  it 
entered  the  compressor.  Reference  to  Table 
V.  (page  127)  shows  that  I  Ib.  of  ammonia 
gas  at  24.5  Ibs.  absolute  pressure  and  o°  Fahr. 
has  a  volume  of  11.917  cubic  feet,  and  at 
24.75  Ibs.  and  o°  Fahr.  11.794  cubic  feet; 


IO4  Theoretical  and  Practical 

therefore,  at  the  absolute  pressure  of  24.7 
Ibs.,  the. volume  of  I  Ib.  of  ammonia  gas 
would  be  1 1. 8 1 86  cubic  feet.  The  effectual 
displacement  of  the  compressor  was  114,005 
cubic  feet  per  24  hours,  so  the  number  of 
Ibs.  of  ammonia  circulated  would  be  (i  14,005 
4-  1 1. 8 1 86  =  )  9,646  per  24  hours.  The 
latent  heat  of  vaporization  we  have  already 
seen  was  561,  therefore  (9,646  X  561  =) 
5,411,406  thermal  units  would  be  absorbed 
by  the  ammonia.  But  the  temperatures  of 
the  ammonia  at  the  supply  and  discharge 
manifolds  of  the  refrigerator  were  respec- 
tively 69°  and  o°  Fahr.,  and,  consequently, 
as  the  ammonia  itself  had  to  be  cooled 
sixty-nine  degrees,  the  available  number  of 
thermal  units  would  be  reduced  to  (5,411,^ 
406  —  (9,646  X  69  X  0.508)  =)  5,073,244,  or 
(5,073,244-^-284,800=)  17.81  tons  of  ice  per 
24  hours,  showing  that  the  loss  due  to  the 
superheating  of  the  gas  only  eight  degrees 
in  its  passage  from  the  refrigerator  to  the 
compressor  amounted  to  (17.81  —  17.49=) 
0.32  ton,  or  about  one-third  of  a  ton  of  ice 
per  24  hours. 


If  the  liquid  anhydrous  ammonia  piping 
between  the  condenser  and  the  refrigerator 
and  the  ammonia  gas  piping  between  the  re- 
frigerator and  compressor  had  been  covered 
with  a  thoroughly  non-conducting  material, 
the  refrigerating  efficiency  of  the  plant  would 
have  been  : 

Gas  entering  Compressor  at   )          9,646  Ibs. 

o°  Fahr $     5,411,406  Thermal  units. 

Ammonia  cooled  from  62°  to 

o°  Fahr.   (9,646  X  62  X 

0.508) 303,810         "  " 


Effective  Thermal  Units  =  5,107,596 


or  (5, 107,596 -f-  284,800  =)  17.93  tons  °f  ice— being  an 
increase  of  (17.93—  *  7-49=0  °-44>  or  nearly  half  a  ton 
of  ice  per  24  hours. 

As  the  question  of  condensing  water  has 
been  fully  discussed  previously,  it  is  consid- 
ered unnecessary  to  go  further  into  figures 
in  relation  to  this  part  of  the  subject. 


106  Theoretical  and  Practical 


CHAPTER    XI. 

CALCULATION  OF  THE  MAXIMUM  CAPACITY 
OF    A    MACHINE. 

As  the  capacity  of  a  machine  is  propor- 
tional to  the  quantity  of  anhydrous  ammonia 
circulated,  it  is  evident  that  if  the  ammonia 
valves  are  regulated  so  as  to  give  a  brine 
temperature  of  o°  Fahr.,  the  refrigerating 
efficiency  expressed  in  tons  of  ice  will  not  be 
nearly  so  great  as  when  the  valves  are  ad- 
justed for  a  28°  Fahr.  brine  temperature. 
The  amount  of  anhydrous  ammonia  circu- 
lated at  the  former  temperature  would  only 
be  one-half  the  weight  circulated  at  the  iat- 
ter  temperature. 

If  the  brine  temperature  were  above  28° 
Fahr.  it  would  be  incapable  of  doing  prac- 
tical refrigerating  work  —  that  is,  the  tem- 
perature would  be  too  high  to  freeze  water 
sufficiently  quick  to  be  of  any  practical 
value. 


Ammonia  Refrigeration.  107 

Twenty- eight  degrees  Fahrenheit  is  there- 
fore the  highest  practical  brine  temperature, 
and  in  order  to  maintain  that  the  ammonia 
must  boil  at  14°  Fahr.,  which  latter  tempera- 
ture is  obtained  by  regulating  the  ammonia 
valves  so  that  a  suction-gauge  pressure  of 
28^  Ibs.  is  maintained. 

Therefore,  in  calculating  the  maximum  ca- 
pacity of  a  machine  we  must  figure  upon  the 
suction-gauge  pressure  being  28 J^  Ibs.  and 
the  suction  temperature,  say,  20°  Fahr.  at  the 
point  where  the  gas  enters  the  compressor. 

PREPARATION    OF   ANHYDROUS 
AMMONIA. 

The  principal  parts  of  the  apparatus  neces- 
sary for  the  production  of  anhydrous  ammo- 
nia from  26°  ammonia  are  : 

(1)  An  iron  cylinder  (still)  about  2  feet  in 
diameter  by  3  feet  deep. 

(2)  An   iron   cylinder   (column)    about    10 
inches  in  diameter  by  2  feet  high. 

(3)  A  tank  (condenser)  about  3  feet  in  di- 
ameter by  4*4  feet  deep. 


Io8  Theoretical  and  Practical 

(4)  Two  iron  cylinders  (separators)  about 
10  inches  in  diameter  by  5^  feet  high. 

(5)  An  iron  vessel  (dehydrator)  about  3^ 
feet  long  by  2  feet  broad  and  2  feet  deep. 

CONSTRUCTION  OF  APPARATUS. 

The  apparatus  should  be  of  sufficient 
strength  to  withstand  a  pressure  of  60  Ibs. 
on  the  square  inch.  Its  general  arrange- 
ment is  shown  in  section  in  Fig.  15,  in  which 
A  is  the  still,  the  contents  of  which  is  heated 
by  the  steam  coil,  a.  The  ammonia  gas,  to- 
gether with  a  little  water  vapor,  pass  off 
through  b  into  the  column  B,  and  coming  in 
contact  with  the  plates  c,  the  larger  portion 
of  the  water  separates  and  flows  back  into  A 
by  the  pipe  d,  while  the  ammonia  gas  passes 
upwards  through  the  holes  e,  and  over  to  the 
condenser,  C,  After  leaving  the  condenser 
the  gas  passes  through  the  two  separators  D, 
D  (where  the  water  condensed  in  C  sepa- 
rates) into  the  dryer,  E,  where,  coming  in 
contact  with  lime  placed  on  the  perforated 
plates  f,  it  is  rid  of  its  last  traces  of  moisture. 


Ammonia  Refrigeration.  109 

It  is  then  drawn  through  the  pipe  /  into  the 
suction  of  the  ammonia  engine. 

The  plates  in  B  are  -separated  by,  and  rest 
on,  the  iron  rings  /'.  The  head  of  the  still 
and  bottom  end-plate  of  B,  together  with  the 
connections  b  and  d,  may  be  conveniently 
cast  in  one  piece. 

CONDENSER- WORM. 

An  efficient  worm  for  the  condenser,  C, 
may  be  cheaply  and  easily  made  of  heavy 
lead  pipe. 

It  is  advisable  to  place  a  cock  or  valve  on 
the  connection  between  B  and  C,  so  that 
when  the  spent  water  is  drawn  from  the  still, 
the  gas  contained  in  the  rest  of  the  apparatus 
will  not  escape.  However,  it  is  not  abso- 
lutely necessary  to  have  a  cock  or  valve  at 
that  point,  because  if  the  water  is  carefully 
run  off  no  gas  will  escape. 

After  the  still,  A,  has  been  charged  it  is 
slowly  heated  by  the  coil,  a,  to  a  tempera- 
ture of  about  2 1 2°  Fahr.  When  the  gauge, 
k,  registers  25  to  30  Ibs.  pressure  the  valve 


1 1  o  Theoretical  and  Practical 

connecting  /  with  the  suction  of  the  c  m- 
pressor  (of  the  ammonia  engine)  is  opened 
and  the  engine  run  so  as  to  maintain  the 
pressure  of  25  to  30  Ibs. 


WHY   STILL   is  WORKED   UNDER 
PRESSURE. 

The  reason  for  running  the  still  under  a 
pressure  is  to  enable  the  contents  of  the  still 
being  heated  up  to,  or  slightly  above,  the 
normal  boiling-point  of  water  without  al- 
lowing the  water  to  boil  —  thus  driving  off 
the  whole  of  the  ammonia,  while  only  a 
minimum  quantity  of  the  water  is  vapor- 
ized. 

After  the  still  has  been  heated  for  about 
an  hour,  a  small  quantity  (about  a  teaspoon- 
ful)  should  be  drawn  off  and  tested  with 
acid  litmus  paper,  and  as  soon  as  it  ceases 
to  turn  the  paper  blue  it  may  be  understood 
that  the  contents  of  the  still  have  been  ex- 
hausted of  ammonia  and  that  the  charge  is 
*'  spent." 


Ammonia  Refrigeration.  1 1 1 

BEST  TEST  FOR  AMMONIA. 

A  better  method  for  telling  when  the 
charge  is  spent,  is  to  have  a  small  cock  in 
the  head  of  the  still,  and,  opening  it  slightly, 
test  the  escaping  vapors  with  a  piece  of  tur- 
meric paper.  If  the  paper  is  turned  brown, 
the  whole  of  the  ammonia  has  not  been 
driven  off,  but  if  it  still  retains  its  yellow 
color  the  charge  is  thoroughly  exhausted. 

The  spent  water  is  run  off  from  the  still 
by  the  cock  g,  and  after  the  still  has  cooled 
down  it  is  ready  for  re-charging. 

WATER  FROM  SEPARATORS. 

Very  little  water  accumulates  in  the  sepa- 
rators D,  D,  if  the  pressure  in  the  still  is 
carefully  watched,  but  the  cocks  /i,  h  should 
be  cautiously  opened  (care  being  taken  that 
no  gas  escapes)  after  about  the  fifth  or  sixth 
distillation,  and  if  any  water  runs  out  it 
should  be  saved,  as  it  will  be  saturated  with 
ammonia  gas,  and  therefore  ought  not  to  be 
thrown  away,  but  should  be  placed  in  the 
drum  containing  the  26°  ammonia. 


1 1 2  Theoretical  and  Practical 

LIME  FOR  DEHYDRATOR. 

The  lime  in  E  should  be  examined  occa- 
sionally by  removing  the  hand-hole  plate,  F, 
and  if  it  has  slaked  to  any  great  extent  the 
cover  on  E  should  be  removed  and  the  plates 
/taken  out  and  replenished  with  newly  burnt 
lime  broken  in  pieces  about  the  size  of  a 
hen's  egg.  The  lime  should  not  be  laid  more 
than  one  layer  deep  on  each  plate. 

The  amount  of  26°  ammonia  that  has  to  be 
distilled  in  order  to  obtain  a  given  quantity 
of  anhydrous  ammonia  can  be  determined  by 
the  use  of  Table  II. 


YIELD   OF   ANHYDROUS   FROM   26° 
AMMONIA. 

Let  it  be  supposed  that  50  gallons  of  an- 
hydrous ammonia  are  required.  By  referring 
to  the  table  it  is  seen,  under  the  heading 
"  Per  Cent,  by  Volume,"  that  26°  ammonia 
contains  38.5  per  cent,  of  anhydrous  ammo- 
nia, therefore,  as  50  gallons  of  anhydrous 
ammonia  are  required  it  will  be  necessary  to 


Ammonia  Refrigeration. 


distill    (38.5  :  50  : :  100)    130   gallons  of   26° 
ammonia. 

It  is,  of  course,  always  advisable  to  try  the 
strength  of  the  26°  ammonia,  as  it  is  liable 

TABLE     II. 


SOLUTION. 


ANHYDROUS  AMMONIA, 


Weight  of  In. 

£^  f  ° 

a 

c 

""     Tl      fl      C 

G              • 

j^ 

^ 

•. 

'o 

Illlj 

.S  c  '| 

it 

c  "Si 

[1 

-ri  ® 

3 

o    r  o  >•  •- 
«  4  'S  u  -2 

tA   —    "3 

V   J3 

u  .9 

u  « 

11 

*  s, 

"o 
PQ 

S    rt  -C    c    ° 
Jfe   a  o^ 

>0°^l^l 

o      -5 

^ 

1 

34-7 

7.09 

26° 

494 

3-°77 

59-5 

43-4 

32.8 

7.17 

38° 

4^6 

2.841 

54-9 

39-6 

31.0 

7-25 

50° 

419 

2.610 

50-7 

36.0 

29.0 

7-34 

62° 

382 

2-379 

46.0 

32-5 

27.2 
26.0 
25.6 

7.42 
7-48 
7-50 

74° 
83° 
86° 

346 
320 

2.156 
1-993 
1-937 

41.7 
38-5 
37-5 

29.1 
26.6 
25.8 

237 

7-59 

98° 

277 

1.726 

33-4 

22.8 

22.2 

7.67 

110° 

244 

1.520 

29.4 

19.7 

to  vary  somewhat  ;  and  should  it  be  found 
stronger  or  weaker  (/.  c.,  lighter  or  heavier  in 
gravity)  than  the  supposed  strength,  an  al- 
lowance can  be  made,  by  means  of  Table  II., 


1 1 4  Theoretical  and  Practical 

when  calculating  the  quantity  necessary  to 
be  distilled  to  yield  a  given  quantity  of  an- 
hydrous ammonia. 

The  cost  of  preparing  anhydrous  ammo- 
nia from  26°  ammonia  is  very  small,  and  the 
difference  in  the  price  between  the  "  home 
prepared"  and  the  "commercial"  anhydrous 
will  very  soon  pay  for  the  cost  of  the  ap- 
paratus. 

In  most  works  were  freezing  plants  are  in 
use  there  are  ample  large-sized  pipmg,  small 
tanks  or  odd  pieces  of  apparatus  lying  in 
disuse  which  could  be  easily  fitted  together 
on  the  principle  of  Fig.  15,  and  at  a  total 
cost  of,  say,  $150. 

The  price  of  commercial  anhydrous  am- 
monia is  44.88c.  per  lb.,  and  the  price  of 
commercial  26°  ammonia  is  6c.  per  lb. 

Twenty-six  degree  ammonia  contains  26.6 
per  cent,  by  weight  of  anhydrous  ammonia, 
therefore  3.76  Ibs.  of  26°  ammonia  g;ve  I  lb. 
of  anhydrous  at  a  cost  (irrespective  of  labor) 
of  22.56c. 


Ammonia  Refrigeration. 


5— 


116 


Theoretical  and  Practical 
TABLE    III. 


PRESSURE. 

I. 

yZ 

rz     o 
o 
M 

«J 

rt 

B 

i 

5 

PRESSURE. 

1 

W 
C 

1 

1 

c 

i 

rt 

,j 

Absolute. 

V 
H 
3 
rt 

O 

1 

Absolute. 

i 

• 

o 

IO.C9 

—  4.01 

—40 

579-7 

58.00 

43-3° 

28.9 

537-6 

11.00 

—3.70 

—39 

579-1 

59-41 

44.71 

3O.O 

536.9 

12.31 

—2.39 

—35 

576-7 

6O.OO 

45-30 

3°-6 

536.5 

13.00 

—1.70 

—32-7 

575-3 

61.50 

46.80 

32-0 

535-7 

14-13 

—0-57 

—30 

573-7 

62.OO 

47-3° 

32.3 

535-5 

14.70 

^o.oo 

—28.5 

S72-3 

63.00 

48.30 

33-o 

535-o 

15.00 

4-0.30 

—  27.8 

571-7 

64.00 

49-3° 

33-7 

534-6 

16.17 

1.47 

-25 

570.7 

65-93 

51-23 

35-o 

533-8 

16.71 

2.OI 

—  22 

568.9 

67.00 

52-30 

35-8 

533-3 

17.00 

2.30 

—21.8 

568.7 

69.00 

54-3° 

37-2 

532-4 

18.45 

3'75 

—  20 

567-7 

7I.OO 

56-30 

38.6 

531-5 

19.00 

4-3° 

—  18.9 

567-0 

73.00 

58-30 

40.0 

530-6 

20.99 

6.29 

-15 

564.6 

74.07 

59-37 

41.0 

53°.° 

21.27 

6-57 

—  13 

563-4 

75.00 

60.30 

41-5 

529-7 

22.10 

7.40 

—  12 

562.8 

70.00 

61.30 

42.2 

529.2 

22.93 

8.23 

—  II 

562.2 

78.00 

63-30 

43-4 

528.5 

23-77 

9.07 

10 

561.6 

80.66 

65.96 

45-o 

527-5 

24.56 

9.86 

—  9 

561.0 

88.96 

74.26 

50.0 

524-3 

25.32 

10.62 

—  8  j 

560.4 

92.OO 

77-30 

5!-4 

523-4 

20.08 

11.38 

—  7 

559-8 

95.00 

80.30 

53-2 

522.3 

26.84 

12.14 

—  6 

559-2        97.93 

83-23 

55-o 

521.1 

27-57 

12.87 

-  5 

558.5 

100.00 

85.30 

56.1 

520.4 

28.09 

!3-39 

—  4 

557-9 

104.84 

90.14 

59-o 

518.6 

28.64 

I3.94 

—  3 

557-3 

107.60 

92.90 

60.0 

5!7-9 

29.17 

14.47 

—  2 

556.7 

IIO.OO 

95-30 

61.1 

517.2 

29.76 

15.06 

—       I 

556.1 

115.00 

100.30 

63-5 

515.7 

30.37 

15-67 

^©(zero) 

555-5 

118.03 

103-33 

65.0 

515.3 

31.00 

16.30 

+  L4 

554-6 

119.70 

105.00 

66.0 

514.1 

32.00 

17.30 

3-5 

553-4 

123.59 

108.89 

68.0 

512.8 

33-66 

18.96 

5 

552.4 

125.20 

112.50 

69.0 

512.2 

35-00 

20.30 

5-9 

551-9 

127.21 

114.51 

70.0 

5II-5 

36.00 

21.30 

7 

551-2 

138.70 

124.00 

74-5 

508.6 

37-00 

22.30 

8.2 

550.5 

141.25 

I27-55 

75-o 

508.3 

38.55 

23-85 

10 

549-3 

144.67 

129.97 

77-o 

507.0 

39.00 

24.30 

10.6 

549-0 

149.70 

135-0° 

78.5 

506.0 

4O.OO 
42.2O 

25-30 
27/50 

12 

14 

548.1 
546.8 

154.11 

161.70 

I39-4I 
147.00 

80.0 
82.5 

504.7 
5°3-5 

Ammonia  Refrigeration. 

TABLE     III.  —  Continued. 


II/ 


PRESSURE. 

PRESSURE. 

a 
e 

c 

| 

8 

J3 

.            *    |             « 

1 

& 

04 

bfl 

I 

^              ^     o                 il 

3 

1 

3        I          '  J 

* 

rt 
O 

'o 

3 

42.93 

44-00. 

28.23 
29.30 

15                 546.3 
i  6              545-6 

165.70 
166.70 

I5I.OO 
152.00 

84.5 
84.9 

502.1 
501.8 

45.00 

30.30 

17              545-o 

167.86 

I53-I6 

85.4 

501.6 

46.00 
47.00 
47-95 

3I-30 
32-30 

33-25 

18.1 
19.1 
20 

544-3 

543-7 
543-1 

,   168.30 
168.70 
I75-70 

154.00 

161.00 

86!o 
88.5 

501.2 
500.8 

499-5 

49.00 

34-3° 

21.  1                542.5 

182.80 

168.10 

90.0 

498.1 

50.00 

35-30 

22-3 

541-7 

194.80 

180.10 

95.0 

495-3 

50-67 

35-97 

23 

541-3 

204.  70 

190.00 

98.0 

493-3 

51.00 

36-3° 

23-3 

54I-I 

215.14 

200.44 

IOO.O 

491-5 

52.00 

37-3° 

24 

540.7 

224.40 

209.70 

104.0 

489.4 

53-43 

38-73 

25 

540.0 

257.20 

242.50 

113.0 

483-4 

54-oo 

39-3° 

25-5 

539-7 

293.20 

278.50 

I22.O 

476.4 

55-oo 

40.30 

26.3 

539-3 

318.40 

I3I.O 

471.4 

56.00 

41.30 

27.1 

538.7 

377-20 

352.50 

140.0 

465.4 

57-oo 

42.30 

28 

538.2 

Theoretical  and  Practical 
TABLE    IV. 


M 

s.s  c 

TEMPERATURE  OF  SUCTION  =  0°  FAIIR. 

111 

Absolute  Suction  Pressure. 

CJ 

20 

22 

25 

27  |  30  |  32    35 

37    40 

24   45 

90 

199 

I84 

I65 

153 

138 

129 

116 

109    98 

92 

83 

95 

208 

193 

173 

161 

146 

137 

124 

118 

105 

99 

90 

100 

216 

2O  I 

181 

169 

I  S3 

144 

Hi 

123 

113 

io5 

97 

105 

224 

208 

1  88 

177 

161 

137 

130 

119 

113 

103 

no 

232 

215 

196 

183 

1  66 

ISS 

126 

119 

109 

115 

239 

223 

203 

191 

174 

164 

151 

143 

132 

I2S 

"5 

1  20 

245 

230 

211 

197 

181 

171 

I|8 

149 

138 

121 

125 

253 

237 

216 

204 

187 

177 

164 

IS6 

144 

137 

127 

130 

261 

244 

222 

2IO 

193 

169 

161 

ISO 

142 

132 

135 

266 

250 

229 

216 

199 

189 

175 

167 

iSS 

I48 

138 

140 

273 

256 

23  S 

222 

20S 

194 

181 

172 

161 

ISS 

141 

145 

279 

262 

240 

228 

2IO 

197 

186 

178 

166 

158 

15° 

285 

268 

246 

233 

216 

206 

191 

183 

I7i 

164 

i  S3 

155 

291 

273 

2S2 

239 

221 

211 

197 

1  88 

176 

169 

iS8 

1  60 

165 

296 
302 

279 
285 

257 
262 

244 
249 

226 
232 

216 
221 

202 
206 

$ 

181 

185 

173 
178 

163 
167 

bo 

JJ  S  4J 
3  ^  M 

TEMPERATURE  OF  SUCTION  =  5°  FAHR. 

III 

Absolute  Suction  Pressure. 

CJ 

20 

22 

25 

27 

30 

32 

35 

37 

40 

42  |  45 

90 

206 

191 

172 

1  60 

145 

13.5 

123 

US 

104 

98 

89 

95 

215 

2OO 

1  80 

1  68 

IS3 

143 

130 

122 

III 

96 

IOO 

223 

208 

186 

176 

160 

138 

130 

119 

112 

103 

105 

231 

216 

195 

183 

I67 

I58 

145 

137 

125 

119 

109 

no 

239 

223 

203 

190 

174 

165 

151 

H3 

132 

125 

"5 

us 

247 

231 

210 

198 

181 

171 

159 

ISO 

139 

132 

122 

120 

254 

238 

218 

204 

188 

I78 

163 

ij6 

145   137 

127 

125 

261 

245 

222 

211 

194 

184 

170 

163 

ISO 

H3 

133 

HO 

268 

2SI 

230 

217 

200 

190 

176 

1  68 

156 

149 

139 

135 

273 

258 

236 

223 

206 

196 

182 

174 

162 

155 

145 

140 

281 

264 

242 

229 

212 

202 

1  88 

179 

I67 

1  60 

ISO 

145 
150 

287 
293 

270 

276 

248 
254 

235 
241 

218 

223 

207 
213 

$ 

185 
190 

172 

I78 

I65 
170 

155 
1  60 

ISS 

299 

282 

2S9 

246 

229 

218 

204 

195 

183 

175 

165 

1  60 

3°5 

287 

265 

2.S2 

234 

223 

209 

200 

1  88 

1  80 

170 

165 

3H 

293 

270 

257 

239 

229 

214  205 

192 

185 

173 

Ammonia  Refrigeration. 

TABLE     IV.  —  Continued. 


119 


Absolute 
Condensing 
Pressure. 

1  EMPERATURE  OF 

SUCTI  >NT  = 

-  10°  FAHR. 

Absolute  Suction  Pressure. 

20 

22 

25 

27 

30  |  32  |  35    37    40 

42 

45 

90   213 

IQS 

I78 

I67 

I5I 

141 

129 

121 

IIO 

104 

96 

95  !  222 

207 

I87 

159 

ISO 

136 

I29 

118 

III 

I  O2 

ioo  :  231  i  215 

183 

167 

157 

144 

136  j  125 

118 

109 

105  ,  239  223 

2O2 

190 

174 

164 

151 

H3 

132 

125 

"5 

no  247 

229   2IO 

197 

181 

172 

158 

I5° 

139 

132 

122 

"5 

254  |  238   217 

20S 

188 

178 

164 

156 

H5 

138 

128 

120 

26l 

245   226 

211 

:95 

185 

171 

163 

151 

144 

134 

125 

269 

252   231 

218 

201 

191 

177 

169 

1.57 

150 

140 

130 

27S 

259   237 

224 

207 

197 

183 

175 

103 

155 

145 

I3S 

282 

266  i  244 

231 

214 

203 

189 

181 

168 

161 

151 

I4O 

289  I  272 

2SO 

237 

219 

209 

195 

1  86 

174 

167 

156 

H5 

295  278 

2S6 

244 

22  S 

211 

200 

192 

179 

172 

l62 

150 

301 

284 

262 

248 

231 

22O 

20S 

197 

I»S 

177 

167 

155 

307 

290 

266 

254 

236 

225 

211 

202 

190 

•182 

172 

1  60 

3n 

29  S 

273 

259 

24I 

231 

216 

207 

195 

187 

176 

105 

319 

301 

278 

265 

247 

236 

221 

212 

199  192 

181 

bd 

TEMPERATURE  OF 

SUCTION  =  15°  FAHR. 

!U 

Absolute  Suction  Pressure. 

CJ 

20 

22 

'25  i  27 

30 

32 

35    37 

40 

42  i  45 

90 

221 

205 

185  ;  173 

I58 

148  135  127 

117 

IIO 

IOI 

95 

230 

214 

194  i  182 

166 

IS6  J43 

135   I24 

117 

1  08 

IOO 

238 

222 

202  i  189 

173 

164 

151 

142 

131 

124 

US 

I05 

246 

230 

209  i  197 

181 

171 

I58 

150 

138 

131 

121 

IIO 

254 

238 

2  1  7  204 

1  88 

178 

I64 

I56 

145 

138 

128 

115  262  246 

224   212 

195 

182 

171 

163 

152 

144 

134 

120 

269 

253 

233  218 

202 

192 

I78 

I69 

158 

'5° 

I4O 

125 

276 

260 

238   225 

208 

198 

I84 

176 

163 

146 

I30   283 

267 

245  i  232 

2I4 

204 

191 

181 

170 

162 

152 

135   290 

273 

251  !  238 

221 

210   196 

187  175 

1  68 

I58 

140 

297 

279 

257  '  244 

226 

216 

202 

193  181 

173 

163 

145  ;  303   286 

263  I  250 

232 

221  207  199  i  86 

179 

1  68 

150  ;  309  292 

269  i  256 

238 

227  213  204  192  1  184 

173 

155  3*5 

298 

275  261 

244 

232  j  218  209  197  189 

178 

1  60 

32I 

3°4 

281  1  267 

249 

238  ;  223  i  214   2O2 

194  i  183 

165 

327 

309 

286  272  ' 

254 

243  :  228  219  206  199  188 

120 


TJicoretical  and  Practical 

TABLE   IV.—Contimtai. 


S.SB 

TEMPERATURE  OF  SUCTION  =  20°  FAHR. 

||| 

Absolute  Suction  Pressure. 

'u 

20 

22 

25    27    30 

32 

35 

37 

40 

42 

45 

90 

228 

212 

192  180  164 

154 

141 

133 

123 

116 

106 

95 

237 

221 

2O  I 

189  j  172 

I63 

149 

141 

I30 

123 

114 

IOO 

245 

230 

209 

196   1  80 

171 

157 

149 

137 

131 

121 

105 

253 

237 

217 

203 

1  88 

178 

164 

I56 

I44 

138 

128 

IIO 

262 

245 

224 

211 

195 

185 

171 

162 

15° 

144 

134 

115 

269 

253   23I   2I9 

202  192 

178 

I69 

I58   151 

140 

120 

277   260   240  |  226 

209  198 

185 

176 

164   157 

I4-.3 

125 

284   267  j  245   233 

215  205  191 

183 

170   163 

I30 

291  :  274 

252 

239 

222   211 

197 

1  88 

176  i  169 

158 

135 

298  !  281 

260 

245 

228   219 

203 

194 

182   174  ; 

1  6l 

140 

305 

287 

265 

251 

234 

223 

209 

200 

i  88  181  ' 

169 

145 

311 

294 

271  ;  258 

240  j  226   214 

205 

193  185  ! 

'75 

150 

317 

300 

277 

263 

245 

235   220 

211 

198  j  191  ; 

1  80 

155 

323 

306 

283  |  269 

251 

240 

225 

216 

203  196 

185 

1  60 

329 

3I2 

288 

275   256   245 

230 

221 

209 

201 

190 

I65 

335 

317 

294 

280 

262   25I   235 

226 

213  206 

195 

tat 

TEMPERATURE  OF  SUCTION  = 

--  25°  FAHR. 

a'7  " 

o  £  % 
3«| 

Absolute  Suction 

Pressure. 

U 

20 

22  !  25    27 

30  !  32 

35 

37  !  40 

1  42  |  <L5 

90 

235 

219 

199  1  86 

171  i  161 

148 

140 

129 

122 

III 

95 

244 

228 

207  195 

179 

169 

ISS 

I48 

136 

129   I2O 

1  00 

252 

237 

216  203 

187 

177 

163 

155 

144 

137   127 

i°5 

26l 

245 

224   211 

194 

183 

171 

1  62 

ISO 

144   134 

no 
US 

269 

277 

251  230  218 
260  1  239  226 

200 
209 

191 

198 

178 
184 

I69 
I76 

155 
164 

I5O   140 
157   147 

120 

284 

268 

247   232 

216  205 

191 

182 

171 

163 

i.53 

I2S 

292 

27S 

253   240 

222 

212 

197 

189 

177 

169 

159 

130 

299 

282 

259   246 

229 

218 

204 

195 

1*3 

175 

165 

1.15 

306 

289 

267   253 

235 

224 

210 

201  i  88 

181 

140 

3*3 

295 

271   259 

241 

230 

216 

207  194 

187 

1  76 

145 

301 

278   265 

247 

236 

221 

212   200 

192 

181 

150 

325 

308 

284   271   253 

242 

227 

218  205 

197 

187 

155 
160 
'165 

5 

344 

314 
320 
324 

290  i  277 
296   282 
302  ;  288 

258   247 
264  I  253 

269  !  258 

232 
237 
243 

223   2IO 

228  216 

233   220 

203 
208 
213 

192 
197 

201 

Ammonia  Refrigeration. 

TABLE   IV .—Continued. 


121 


bfl 

TEMPERATURE  OF  SUCTION  =  30°  FAHR. 

l|| 

Absolute  Suction  Pressure. 

U 

20 

22 

25  |  27 

30 

32    35 

37 

40 

42 

45 

90 

242 

226 

206 

193 

i/7 

I67 

154 

146 

134 

128 

118 

95 

25  I 

235 

214 

202 

185 

176 

162 

154 

I42 

136 

I25 

IOO 

260 

244 

223 

2IO 

193 

184 

170 

161 

143 

133 

IO5 

269 

252 

23I 

218 

201 

191 

177 

169 

157 

140 

IIO 

277 

260 

239 

226 

208 

199 

184 

176 

164 

157 

115 

285 

268 

246 

233 

216 

205 

191 

183 

171 

164 

153 

120 

292 

275 

255 

240 

223 

212 

198 

189 

177 

170 

159 

125 

300 

283 

260 

247 

230 

219 

204 

196 

183 

I76 

165 

I30 

307 

290 

267 

254 

225 

211 

202 

190 

182  j  171 

U5 

3H 

297 

274 

260 

242 

232 

217 

208 

1  88 

177 

140 

321 

303 

280 

266 

248 

237 

223 

214 

201 

193 

183 

145 

327 

3°9 

286 

273 

254 

240 

228 

2igr 

2O7 

199 

1  88 

150 

334 

316 

292 

278 

260 

249 

234 

225 

212 

204 

193 

155 

340 

322 

298 

284 

266 

255 

240 

230 

217 

2IO 

199 

1  60 

346 

328 

3°4 

290 

271 

260 

245 

234 

223 

215 

165 

352 

334 

310 

296 

277 

265 

250 

241 

230 

220 

208 

90 

95 

IOO 

105 
no 

"5 

120 

125 
I30 

135 

140 


155 
1 60 

165 


TEMPERATURE  OF  SUCTION'  =  32°  FAHR. 

Absolute  Suction  Pressure. 

20 

22 

25    27 

30 

32 

35 

37 

40    42 

45 

245 

229 

209 

196 

179 

I70 

157 

148 

137 

130 

I.  "I 

254 

238 

217 

205 

1  88 

I78 

165 

157 

138 

128 

263 

247 

225 

213 

196 

1  85 

173 

164 

*53 

H5 

135 

272 

257 

234 

221 

204 

194 

1  80 

172 

'59 

142 

280 

263 

24I 

228 

211 

201 

I87 

I78 

167 

1S9 

149 

288 

271 

249 

236 

218 

208 

194 

I85 

!74 

1  66 

*55 

295 

278 

256 

243 

226 

215 

201 

192 

1  80 

172 

162 

3°3 

286 

263 

250 

232 

222 

207 

199 

1  86 

178 

1  68 

310 

293 

270 

256 

239 

228 

213 

204 

192 

184 

174 

3'7 

300 

277 

263 

245 

234 

22O 

21  I 

198 

190 

1  80 

324 

306 

283 

269 

251 

240 

226 

216 

204 

196 

185 

33° 

289 

276 

257 

243 

231 

222 

209 

203 

191 

337 

319 

295 

28l 

263 

252 

237 

227 

215 

207 

196 

343 

325 

301  j  287 

269 

257 

243 

233 

220 

212 

201 

350 

3°7 

293 

274   263 

248 

238 

226 

218 

206 

355 

337 

3'3  299 

280   268 

253 

244 

233 

22^ 

211 

122        Theoretical  and  Practical 

TABLE  IV  '.—Continued. 

M 

§f  s 

.  TEMPERATURE  OF  SUCTION  =35°  FAHR. 

ill 

111 

Absolute  Suction  Pressure. 

<rj£ 

20 

22 

25 

27 

30    22 

35    37    40    42 

45 

90   249 

233 

2I3 

200 

.182 

174 

1  60 

IS2 

MI   134 

I24 

95 

259 

243 

221   2O9 

192 

182 

1  68 

1  60 

148  142 

1^2 

I-OO 

268   251 

229 

217 

2OO 

190 

I76 

1  68 

156  |  149 

139 

105 

276 

259   238   225 

208   198 

184   175 

l63  i  J56 

I46 

no 

285 

267   246   233 

2  i  5  205 

191  I  182 

170  163 

IS3 

"5 

292  275  j  253 

240 

223   212 

I98   189 

178 

170 

159 

120 

3°P 

285  !  260  i  247 

230  i  219 

205 

196 

184 

176 

T66 

125 

308 

290 

268   254 

237 

226 

211 

203 

190 

182 

172 

130 

3'5 

297 

274  !  26l 

243 

232 

217 

208 

196 

1  88 

178 

135 

322 

3°4 

28l   268 

249 

239 

222 

215 

202 

194 

184 

140 

329  311  288 

274 

255 

244 

230  1  221 

208 

200 

189 

145 

335 

317  294 

280 

262 

247 

235  i  226 

213 

205 

IPS 

150 

341  324  300 

286 

268 

257 

241 

232 

219 

211 

200 

i.SS 

348  33° 

300   292 

273 

2b2 

247 

237 

224 

217 

205 

i  bo 
165 

354 
360 

336 
342 

312 
318 

298 
303 

279 
284 

268 

273 

252 

!  257 

243 
248 

230 
235 

222 
227 

2IO 
215 

TABLE    V. 


POUNDS  PER  SQUARE  INCH  ABSOLUTE  PRESSURE. 


ri  ^ 

^ji 

!:    d* 

j^ 

H| 

14.7 

14.7 

Jf 

14.7 

H! 

14.7 

Volume  in  Cubic  Feet  of  On  3  Pound  Weight  of  G  .s. 

O 

2O.OOI       j|     II 

20.505 

21 

20.954 

31  1  2-1.403 

I 

2O.O42 

1     12 

20-545 

22 

20.994 

32 

21-457 

2 

20.096 

13 

20.589 

23     j      21.049 

33 

21.498 

3         20.137 

20.641      j|    24 

21.089 

34 

21-539 

4    j     20.  1  78 

15 

20.  680 

25 

21-130     !  35 

21-593 

5    i    20.233 

16 

20.  722 

1     26 

21.183 

30 

21.634 

6    !    20.273 
7        20.314 

11 

20.777     i   27   i     21.226 
20.818     I    28   i     21.266 

$ 

21.675 
21.729 

8 

20.368 

19 

20.858     ! 

29    ]     21.321 

!    39 

21.770 

9 

20.409 

20 

20.913 

30 

21.362 

40 

21.809 

10 

20.450 

Ammonia  Refrigeration. 

TABLE  V '.—  Continued. 


123 


§ 

a    . 

n<  u 

1° 

H 

POUNDS  PER  SQUARE  INCH  ABSOLUTE  PRESSURE. 

15 

15%     \     i5%     |     15#    ||      16 

16  tf     |    16  M 

16  # 

Volume  in  Cubic  Feet  of  One  Pound  Weight  of  Gas. 

O 

19.600 

19.271 

18.956 

18.651 

18.357 

18.071 

17-793 

I7.524 

I 

19.637 

19.310 

18.995 

18.686 

18.394 

18.108 

17.820 

17-554 

2 

19.690 

19.362 

19.046 

18.737 

18.444 

18.157 

17.878 

17.608 

3 

19-73° 

19.402 

19.085 

18.775 

18.482 

18.194 

17.914 

17.644 

4 

19.770 

19.441 

19.124 

18.813 

18.519 

18.238 

I7-95I 

17.679 

5 

19.823 

19.494 

'9-175 

18.864 

18.569 

18.280 

17.999 

17.727 

6 

19.863 

!9-533 

19.214 

18.902 

18.607 

18.317 

18.036 

17.763 

7 

19.900 

I9-572 

19-253 

18.940 

18.644 

18.354 

18.072 

17.799 

8 

19-957 

19.623 

19.311 

18.991 

18.694 

18.403 

18.121 

17.847 

9 

19-995 

19.662 

19-343 

19.032 

I8.732 

18.440 

18.157 

17.882 

10 

20.036 

i9-703 

19.382 

19.070 

I8.769 

18.477 

18.193 

17.918 

ii 

20.090 

19-755 

19.432 

19.121 

18.819 

18.526 

18.242 

I7.965 

12 

20.133 

'9-795 

19.472 

I9-I59 

18.856 

18.563 

18.278 

18.002 

13 

20.  1  70 

I9-835 

19.511 

19.197 

18.894 

18.600 

'8.315 

13.038 

14 

20.223 

19.885 

i9-563 

19.248 

18.944 

18.649 

18.363 

18.085 

15 

20.263 

19.924 

19.601 

19.286 

18.982 

18.686 

18.399 

18.121 

16 

20.303 

19.964 

19.640 

19.324 

I9.OI9 

18.723 

18.436 

18.157 

17 

20-357 

20.018 

19.691 

19-375 

19.069 

18.772 

18.484 

18.205 

18 

20.396 

20.058 

19-73° 

I9-4I3 

19.107 

18.809 

18.521 

18.241 

19 

20.437 

20.097 

19.769 

I9-451 

19.144 

18.846 

'8-557 

18.276 

20 

20.490 

29.149 

19.821 

19.502 

19.194 

18.895 

18.605 

18.324 

21 

20.523 

20.189 

19.859 

19.540 

19.247 

18.932 

18.642 

18.360 

22 

20.570 

20.  22  1 

19.898 

19.578 

19.298 

18.969 

18.678 

18.396 

23 

20.623 

2O.28l 

19.950 

19.629 

19-33° 

19.018 

18.727 

18.444 

24 

20.663 

20.320 

19.988 

.19-667 

19.376 

'9-055 

18.763 

18.479 

25 

20.703 

20-359 

20.027 

I9-705 

19.410 

19.092 

18.799 

18.515 

26 

20.756 

20.412 

20.079 

I9-756 

19.444 

19.141 

18.848 

18.563 

27 

20.797 

20.451 

20.117 

19.794 

19.482 

19.178 

18.885 

18.599 

28 

20.837 

20.490 

20.156 

19.832 

'9-5'9 

19.215 

18.921 

18.634 

29 

20.890 

20.543 

20.208 

19.883 

19.569 

19.265 

18.969 

18.682 

30 

20.930 

20.582 

20.246 

19.921 

19.607 

19.301 

19.005 

18.718 

31 

20.970 

20.622 

20.285 

'9-959 

19.644 

19-338 

19.042 

18.754 

32 

21.023 

20.674 

20.337 

2O.OIO 

19.694 

19.388 

19.090 

18.802 

33 

21.063 

20.713 

20.375 

20.048 

I9-732 

19.425 

19.127 

18.837 

34 

21.103 

20.  753 

20.414 

2O.O86 

19.769 

19.462 

19.163 

18.873 

35 

21.156 

20.804 

20.466 

20.137 

19.819 

19.511 

19.211 

18.921 

36 

21.197 

20.844 

20.505 

20.175 

19.851 

19.548 

19.248 

18.957 

37 

21.236 

20.884 

20.543 

20.213 

19.894 

19-585 

19.284 

18.993 

38 

21.290 

20.936 

20.595 

20.264 

19.944 

19.634 

19-333 

19.041 

39 

21.330 

20.976 

20.633 

2O.3O2  | 

19.982 

19.671 

19.369 

19.076 

40 

21.370 

21.015 

20.672 

20.340 

20.019 

19.708 

19.405 

19.112 

124                   Theoretical  and  Practical 

TABLE  V.—  Continued. 

£ 

Ijs 

POUNDS  PER  SQUARE  INCH  ABSOLUTE  PRESSURE. 

il 

So 

17 

17  # 

17  y2 

17  &     ||      18 

18%     |     18^ 

18% 

H§ 

Volume  in  Cubic  Feet  of  On3  Pound  Weight  of  Gas. 

o 

17.263 

17.009 

16.763 

16.524 

16.292 

16.065 

15.845 

I5  631 

I 

17.298 

17.044 

16.792 

16.558 

16.325 

16.098 

15.878 

15-663 

2 

17-345 

17.090 

16.843 

16.603 

16.369 

16.142 

15.921 

J5-705 

3 

17.381 

17.125 

16.878 

16.637 

16.403 

16.174 

J5-953 

15-738 

4 

17.416 

17.160 

16.912 

16.670 

16.436 

16.208 

15.984 

15-769 

5 

17.206 

16.958 

16.715 

16.481 

16.251 

16.029 

15.812 

6 

17.498 

17.241 

16.992 

16.749 

16.514 

16.284 

16.062 

15.844 

7 

17-534 

17.276 

17.026 

16.783 

16-547 

16.317 

16.094 

15.876 

g 

17-575 

I7.322 

17.072 

16.828 

16.592 

16.361 

16.137 

I5-9I9 

9 

17.616 

17-357 

17.106 

16.862 

16.625 

16.394 

16.170 

I5-95I 

10 

17.651 

17.392 

17.141 

16.896 

16.658 

16.427 

16.202 

15-983 

H 

17-698 

17.438 

17.186 

16.941 

16.703 

16.471 

16.245 

16.025 

12 

17-733 

17-473 

17.221 

16.975 

16.736 

16.503 

16.278 

16.058 

IT 

17.769 

17.508 

17-255 

17.008 

16.769 

16.536 

16.310 

16.089 

'4 

17.816 

17-554 

17.301 

17.053 

16.814 

16.580 

l6-353 

16.132 

15 

17.865 

17.589 

17-335 

17.087 

16.847 

16.613 

16.386 

16.164 

16 

17.886 

17.624 

17-369 

17.121 

16.880 

16.640 

16.418 

16.196 

17 

17-933 

17.670 

17-415 

17.166 

16.925 

16.690 

16.462 

16.239 

18 

17.969 

I7.705 

17.449 

17.200 

16.958 

16.723 

16.494 

16.271 

in 

18.004 

17.740 

17-483 

I7.234 

16.992 

16.750 

16.526 

16.303 

20 

18.051 

17.786 

17-529 

17.279 

17.036 

16.799 

16.570 

16.345 

21 

18.086 

17.821 

17-563 

17.312 

17.069 

16.832 

16.602 

16.377 

22 

l8.I22 

I7.859 

17-598 

17.346 

17.103 

16.865 

16.634 

16.410 

23 

18.169 

17.902 

17-643 

I7.39I 

17.147 

16.909 

1  6.  6;  3 

16.452 

24 

18.204 

17-937 

17.678 

I7.425 

17.180 

16.942 

16.710 

16.484 

25 

18.239 

17.972 

17.711 

17-459 

17.215 

16.973 

16.743 

16.516 

26 

18.286 

18.018 

17.757 

I7.504 

17.258 

17.018 

16.786 

16.539 

27 

18.322 

18.053 

17.792 

17.538 

17.292 

17.051 

16.818 

16.591 

28 

18.357 

18.088 

17.826 

I7.57I 

17.325 

17.084 

16.851 

16.623 

29 

18.404 

18.134 

17.872 

17.617 

I7.369 

17.123 

16.894 

16.666 

3° 

18.439 

18.169 

17.906 

17.651 

I7-403 

17.161 

16.926 

16.697 

18.475 

18.204 

17.941 

17.685 

I7-436 

17.194 

16.959 

16.730 

32 

18.522 

18.250 

17.986 

I7.730 

17.469 

17.238 

17.002 

16.772 

33 

18.557 

18.285 

18.021 

17.763 

17.514 

17.271 

17-034 

16.804 

34 

18.592 

18.319 

18.055 

17-797 

17-547 

17.304 

17.067 

16.836 

35 

18.639 

18.360 

18.101 

17.822 

17-347 

17.110 

16.879 

36 

18.675 

18.401 

18.135 

17.876 

I7-625 

17.380 

I7.I43 

16.911 

37 

18.710 

i8.435 

18.169 

17.910 

17.658 

17.413 

I7.I75 

16.943 

38 

18.757 

18.482 

18.215 

17-955 

I7-703 

17-457 

17.218 

16.985 

39 

18.792 

18.517 

18.263 

17.989 

I7-736 

17.490 

17.251 

17.023 

40 

18.828  i    18.551 

18.283 

18.002 

17.769 

I7.523 

17.283 

I7-055 

Ammonia  Refrigeration. 

TABLE   V.— Continued. 


125 


g 

II 

V 

H 

POUNDS  PER  SQUARE  INCH  ABSOLUTE  PRESSURE. 

19       |     19X 

19^     |     19  #      |      20 

20  #     |     20  M 

20  K 

Volume  in  Cubis  Feet  cf  Ono  Pound  Weight  of  Gas. 

O 

15.421 

15.220 

15.022 

14.828 

14.641 

H-451 

14-27* 

14.104 

I 

15-454 

15.251 

I5-052 

14.859 

14.671 

14.487 

14.308 

14.132 

2 

15.496 

15.292 

I5-093 

14.899 

14.711 

14.526 

14-347 

14.172 

3 

15.528 

i5-324 

15.124 

14.930 

14.741 

14.551 

14-376 

14.200 

4 

15-559 

15-355 

i5-!57 

14.960 

14.771 

14.584 

14.405 

14.229 

5 

15.602 

I5-396 

15.196 

15.001 

14.811 

14.625 

14.444 

14.268 

6 

I5-633 

I5-427 

15.227 

15-031 

14.841 

I4-655 

14.474 

14.297 

7 

15.665 

15-459 

I5-257 

15.061 

14.871 

14.684 

14-503 

14.326 

8 

I5-707 

15-500 

15.298 

15.102 

14.911 

14.724 

14.542 

14.364 

9 

I5-738 

!5-53o 

15-329 

i5-!32 

14.941 

H-754 

14.571     14.393 

10 

I5-770 

15-563 

16.360 

15-163 

14.971 

H-783 

14.600 

14.419 

ii 

15.812 

15.604 

15.401 

15.203 

15.011 

14.823 

14.639 

14.461 

12 

15.844 

J5-635 

I5-432 

15-238 

15.041 

14.852 

14.669 

14.490 

13 

15.875 

15.666 

15.462 

15.264 

15.071 

14.882 

14.698 

14-519 

M 

I5-9I7 

15.708 

I5-504 

I5-304 

15.111 

17.920 

14-737 

'4-557 

15 

15-949 

I5-739 

15-534 

I5-340 

15.141 

17-95° 

14.771 

14.586 

16 

15.980 

'5-770 

I5-565 

15-365 

iS-^1 

14.981 

14.796 

14.615 

17 

16.021 

15.812 

15.606 

15.406 

15.211 

15.020 

14-835 

14.652 

18 

16.054 

15-843 

15-637 

I5-436 

15.241 

15.050 

14.864 

14.682 

19 

16.086 

I5-874 

15.668 

15.466 

15.271 

15.080 

14.893 

14.711 

20 

16.128 

15.916 

15-709 

T5-5°7 

J5-3" 

15.119 

14.932 

14.741 

21 

16.159 

*5-947 

15-739 

15-537 

i5-34i 

15-  H9 

14.961 

14-779 

22 

16.191 

I5-978 

I5-770 

15.568 

J5-37i 

15.178 

14.991 

14.808 

23 

16.244 

16.020 

15.811 

15.608 

15.411 

15.218 

15-03° 

14.846 

24 

16.265 

16.051 

15.842 

15-638 

I5-44I 

15.252 

15.058    14.875 

25 

16.296 

16.082 

I5-873 

15.669 

I5-47I 

I5-277 

15.088 

14.904 

26 

16.338 

16.124 

15-9I3 

15.709 

i5-5ii 

I5-3I7 

15.127 

14-943 

27 

16.370 

16.155 

15-945 

I5-740 

15-541 

I5-346 

15-152 

14.972 

28 

16.401 

16.186 

15-975 

I5-770 

I5-57I 

I5-376 

15-186 

15.000 

29 

16.444 

16.227 

16.002 

15.811 

15.611 

'5-415 

15.226 

I5-°39 

30 

16.475 

16.259 

16.047 

15.841 

1  15-642 

15-444 

15-254 

15.068 

31 

16.502 

16.290 

16.078 

15.871 

!  15-671 

15-475 

15.283 

I5-C97 

32 

16.549 

16.331 

16.119 

15.912 

15-711 

15-514 

15-322 

I5-I35 

33 

16.580 

16.363 

16.150 

15.942 

15.742 

15-544 

15-352 

15.104 

34 

16.612 

16.394 

16.181 

15-973 

15-  771 

'5-573 

15-381 

I5-I93 

35 

16.654 

*6.435 

16.222 

16.013 

15.811 

15-613 

15.420 

15-231 

36 

16.686 

16.466 

16.253 

16.044 

15.841 

15.642 

15-449 

15.261 

37 

16.717 

16.497 

16.283    16.074 

15.871 

15.672 

15-479 

15.294 

38 

16.759 

16-539 

19.324    16.109  i  I5-911 

15.712 

15-518 

15-323 

39 

16.791 

16.570 

16.355!  16.145 

I5-942 

i5-74i 

15-552 

I5-354 

40 

16.824 

16.602 

16.386    16.175 

15.971 

15-771 

'5-576    15-386 

26 


Theoretical  and  Practical 

TABL E    V.  —  Continued. 


\. 

II 

Eo 
H 

POUNDS  PER  SQUARE  INCH  ABSOLUTE  PRESSURE. 

£1 

21  X     |     21  # 

21:/4    ||      22 

22  X 

22  M 

22  -K 

Volume  in  Cubic  Feet  of  Ono  Pound  Weight  of  Gas. 

O 

13-934 

13.768 

13-605 

13.446 

13.292 

13.140 

12.992 

12.847 

I 

I3-963 

I3-796 

13-633 

13-474 

I3-3I9 

13.167 

13.019 

12.873 

2 

3 

4 

14.001 
14.029 
14.058 

I3-833 
I3.863 

13.890 

18.670 
13.698 

13.726 

13-5" 
13.538 
13-566 

I3-356 

13-383 
13.410 

13.203 
13.230 

I3-257 

I3-054 
13.081 
13.108 

12.905 
12.934 
12.961 

5 

14.096 

13.928 

13-763 

I3-603 

13-447 

I3-293 

13-  H3 

12.996 

6 

14.125 

I3-956 

i3-79i 

13.630 

13-474 

13.320 

13.170 

13.023 

7 

I4-J53 

13.984 

13.819 

13.658 

i3-5oi 

13-347 

13.196 

13.049 

8 

14.191 

14.022 

13.850 

!3-695 

I3-538 

13.383 

13.232 

13.084 

9 

14.220 

14.050 

13.884 

13.722 

I3-565 

13.410 

I3-259 

I3.III 

10 

14.249 

14.078 

13.912 

I3-75° 

13-594 

13-437 

13.285 

I3-I37 

ii 

14.287 

14.116 

13-949 

13-787 

13.629 

13-473 

I3-32I 

13.172 

12 

i4-3I5 

14.144 

13-977 

13.814 

13.656 

I3-500 

I3-348 

I3-I99 

*3 

14-344 

14.172 

14.005 

13.842 

13.683 

I3-527 

13-374 

I3-225 

H 

14.382 

14.210 

14.042 

13-879 

I3-7I9 

I3-563 

13.410 

13.260 

15 

14.410 

14.237 

14.070 

13.906 

13-747 

I3-590 

I3-436 

13.287 

16 

14-439 

14.260 

14.098 

13-934 

13-774 

13.617 

I3-463 

I3-3I3 

17 

14-477 

14.304 

I4-I35 

I3-97I 

13.801 

I3-653 

13-499 

13-348 

18 

14.500 

14-  332 

14.163 

13.998 

13-838 

13.680 

I3-525 

13-374 

19 

H-534 

14-360 

14.191 

14.026 

13-865 

13.706 

13.552 

13.401 

20 

14.572 

17.398 

14.228 

14.063 

13.901 

I3-742 

13.588 

I3-436 

21 

14.001 

14.426 

14.256 

14.090 

13.929 

13.769 

13.614 

13.462 

22 

14.629 

H-455 

14.284 

14.118 

13-95° 

I3-79'J 

13.641 

13.489 

23 

14.668 

14.492 

14.321 

14-154 

13.992 

13-832 

13.076 

I3-524 

24 

14.696 

14.520 

14-349 

14.182 

14.020 

I3-859 

I3.703 

13-550 

25 

i4-725 

14-549 

14-377 

14.210 

14.047 

13.880 

13-73° 

13-577 

26 

14-763 

14.580 

14.414 

14.246 

14.083 

13.922 

I3-765 

13.612 

27 

14.787 

14.615 

14.442 

14.274 

14.110 

13-949 

I3-792 

13.638 

28 

14.825 

14.643 

14.470 

14.302 

14.138 

i>976 

13.819 

13.665 

29 

14.858 

14.680 

I4-507 

I4-338 

14.174 

14.012 

I3-854 

13.700 

30 

14.887 

14.709 

H-535 

14-366 

14.201 

14.039 

13.881 

13.726 

31 
32 

I4-9I5 
14-953 

14-737 
14-775 

14-5^3 
14.600 

14.389 
14.430 

14.229 
14.265 

14.066 
14.102 

13.908 
13-943 

I3-752 
13.788 

33 

14.982 

14.803 

14.628 

14.458 

14.292 

14.129 

13.970 

13.814 

34 

15.010 

14.831 

14.656 

14.485 

i4-3!9 

14.156 

13.996 

13.840 

35 

15.049 

14.869 

14.693 

14.522 

I4-356 

14.192 

14.032 

13.876 

36 

i5-077 

14.897 

14.721 

14.548 

14-383 

14.219 

14.059 

13-902 

37 

15.106 

14-925 

14.749 

14-577 

14.410    14.246 

14.085 

13-928 

3« 

i5-!44 

14.963 

14.786 

14.614 

14.447    14.282 

14.121 

13-963 

39 

15.172 

14.991 

14.814 

14.642 

14.474    14-309 

14.148 

13.990 

40  |  15.201 

15.015 

1-4.842 

14.669 

14.501     14.336 

14.174 

14.016 

Ammonia  Refrigeration.                    127 

TABLE    V.  —  Continued. 

g 

3     . 

POUNDS  PER  SQUARE  INCH  ABSOLUTE  PRESSURE. 

£  -^ 

$£ 

23 

23  % 

23  K 

23^     ||      24 

24^     1     24  y3 

24  K 

So 

1  ! 

1 

^y 

Volume  in  Cubic  Feet  of  One  Pound  Weight  of  Gas. 

0 

12.706 

12.567 

12.421 

12.299 

12.169 

12.041 

11.917 

11.794 

j 

12.732 

12.588 

12-457 

12.324 

12.194 

12.066 

11.941 

11.819 

2 

12.767 

12.627 

12.491 

12-357 

12.227 

12.098 

11.974 

11.851 

3 

12-793 

12.653 

12.516 

12.383 

12.252 

12.123 

11.998 

11.875 

4 

12.819 

12.674 

12.542 

12.412 

12.277 

12.148 

12.023 

11.899 

12.854 

12.713 

12.576 

12.442 

12.310 

12.181 

12.055 

11.932 

7 

12.880 
12.906 

12.739 
12.765 

12.601 
12.627 

12.467 
12.492 

12-335 
12.360 

12.206 
12.230 

12.080 
12.104 

11.956 
11.981 

8 

12.941 

12.799 

12.661 

12.526 

12.394 

12.263 

12.137 

12.013 

9 

12.967 

12.825 

12.686 

12.551 

12.419 

12.288 

12.162 

12.037 

10 

12-993 

12.840 

12.712 

12.576 

12.444 

12.313 

12.186 

12.061 

ii 

13.028 

2.885 

12.746 

12.610 

12.477 

12.343 

12.219 

12.094 

12 

I3-054 

2.911 

12.771 

12.635 

12.502 

12.371 

12.243 

12.118 

J3 

13.080 

2.932 

12.797 

12.661 

12.527 

I2-395 

12.268 

12.142 

H 

I3.H5 

2.971 

12.831 

12.694 

12.560 

12.428 

12.300 

12.174 

15 

13.141 

2-997 

12.857 

12.720 

12.585 

12-453 

12.325 

12.199 

16 

13.167 

13-023 

12.882 

12-745 

12.610 

12.478 

12.349 

12.223 

17 

13.201 

3-°57 

12.916 

12.778 

12.644 

12.511 

12.382 

12.255 

18 

13.228 

3-083 

12.942 

12.804 

12.669 

12.540 

12.406 

12.279 

19 

13-254 

3.109 

12.967 

12.829. 

12.694 

12.560 

12.431 

12.304 

20 

13.288 

3-H3 

13.001 

12.863 

12.727 

12-593 

12.464 

12.336 

21 

13-315 

3.169 

13.027 

12.888 

12.752 

12.618 

12.488 

12.360 

22 

i3-34i 

3-J95 

13-052 

12.913 

12.777 

12.643 

12.512 

12.385 

23 

I3-376 

13.229 

13.086 

12.947 

12.810 

12.676 

12.545 

12.417 

24 

13.402 

I3-255 

13.112 

12.972 

12.835 

12.701 

12.570 

12.441 

25 

13.428 

13.281 

I3-I37 

12.997 

12.861 

12.725 

12.594 

12.465 

26 

13.462 

I3-3I5 

13.171 

13-031 

12.893 

12.758 

12.627 

12.498 

27 

13.488 

I3-34i 

i3-!97 

13.056 

12.919 

12.783 

12-651 

12.522 

28 

I3-5I5 

I3-367 

13.223 

13.082 

12.944 

12.808 

12.675 

12.546 

29 

13-549 

13.401 

13-257 

i3."7 

12.977 

12.841 

12.709 

12.579 

30 

I3-576 

I3-427 

13.286 

13.141 

13.004 

12.868 

12.733 

12.603 

31 

13.602 

J3-453 

13-308 

13.166 

13.027 

12.890 

12.758 

12.627 

32 

I3-637 

13-487 

J3-342 

13.200 

13.060 

12.923 

12.790 

12.659 

33 

13-663 

!3-5i3 

I3-367 

13-225 

13-085 

12.948 

12.815 

12.684 

34 

13.689 

13-539 

!3-393 

13.250 

13.110 

12.974 

12.839 

12.708 

35 

13-723 

13-573 

13-427 

13-284 

I3-I44 

13.006 

12.872 

12.740 

36 

13-749 

13-599 

13-452 

13-309 

13.167 

13.030 

12.896 

12.764 

37 

13.776 

13.629 

I3-478 

J3-334 

i3-I94 

!3.o55 

12.921 

12.789 

38 

13.802 

r3-659 

I3-512 

13-368 

13.227 

13.088 

I2-953 

12.821 

39 

13-837 

13.685 

J3-537 

13-393 

13-252 

i3."3 

12.978 

12.845 

40 

13.863 

I3-7Ii 

13-563 

13-419 

I3-277 

13-138 

13.002 

12.869 

28 


Theoretical  and  Practical 


TABLE    V '.—Continued. 


£ 

3     . 

I  -a 

i)  rrt 

0.^ 

E  o 
H 

POUNDS  PER  SQUARE  INCH  ABSOLUTE  PRESSURE. 

25 

25  y4 

25  K 

25%     | 

26 

ae  y4 

26  X 

25  % 

Volume  in  Cubic  Feet  of  One  Pound  Weight  of  Gas. 

O 

11.675 

".558 

11.440 

"•330 

11.219 

II.  Ill 

11.005 

10.900 

I 

11.699 

11.581 

41.466 

"•353 

11.242 

11.134 

11.027 

10.923 

2 

"•731 

11.613 

11.498 

11.384 

11.273 

11.164 

11.057 

10.952 

3 

"•755 

11.637 

11.521 

11.408 

11.296 

11.187 

II.oSo 

10-975 

4 

11.779 

11.661 

"•545 

11.431 

11.319 

II.  210 

11.103 

10.997 

5 

11.811 

11.692 

11.570 

11.462 

"•350 

1  1  .  240 

"-I33 

11.027 

6 

"•835 

11.716 

"•599 

11.486 

"•373 

11.252 

"-I55 

II.O50 

7 

11.859 

11.740 

11.623 

11.509 

11.396 

11.286 

11.178 

11.072 

8 

11.891 

11.771 

11.655 

11.540 

11.427 

"-3I7 

11.208 

1  1.  102 

9 

11.915 

n-795 

11.678 

11.563 

11.450 

"-339 

11.231 

11.124 

10 

i  1-939 

11.819 

11.702 

11.586 

"•473 

11.362 

11.254 

11.147 

ii 

11.971 

11.851 

"•733 

11.617 

11.504 

"-393 

11.284 

11.177 

12 

n-995 

11.874 

"•753 

11.641 

11.527 

11.415   11.306 

11.199 

J3 

12.019 

11.898 

11.780 

11.664     "-55° 

11.438   11.329 

11.222 

14 
15 

12.038 
12.075 

11.930 
n-954 

11.811 
11.835 

11.695 
11.718 

11.581 
11.604 

11.469   11.359 
11.492   11.382 

11.252 
11.274 

1  6 

12.099 

11.977 

11.858 

11.742  H  11.627 

11.515;  11.405 

11.296 

17 

12.131 

12.009 

11.890 

11.773  !!  "-658 

11.545   11.435    11.326 

18 

12.155 

12.033 

11.913 

11.796     11.681 

11.568   11-457    "-349 

19 

2.179 

12.057 

"•937 

11.819     11.704 

11.591    11.480    11.371 

20 

2.  211 

12.088 

11.964 

11.850  i  11.735 

11.621 

ii-Sio1  11.401 

21 

2-235 

12.112 

11.992 

11.874  1  11.758 

11.644 

"•533 

11.423 

22 

2.259 

12.136 

12.015 

11.897 

11.781 

11.667 

"•555 

11.446 

23 
24 

2.291 
2-3I5 

I2.I6S 
12.192 

12.047 
12.070 

11.928 

"-951  ; 

11.811 
"•835 

11.697 
1  1  .  720 

11.586 
1  1.  608 

11.476 
11.498 

25 

2-339 

12.215 

12.094 

"•975 

11.857 

"•743 

11.631 

11.521 

25 

2-371 

12.247 

12.125 

12.006 

11.888 

11.774 

11.661 

"-55I 

27 

2-395 

12.270 

12.149 

12.029 

11.911 

11.797 

11.684 

,"•573 

0 

2*3 

2.419 

12.294 

12.172 

12.052 

"•935 

11.819 

1  1  .  706 

"•595 

29 

3° 

2-451 
2-473 

12.326 
12.350 

12.204 
12.227 

12.083 
12.107 

11.965 
11.988 

11.850 
11.873 

"•737 
"•755 

11.625 
11.648 

31 

12.499 

12-373 

12.251 

12.130 

12.  on 

11.895 

11.782 

11.670 

32 

I2-53i 

12.405 

12.282 

12.161 

12.042 

11.926 

11.812 

11.700 

33 

12-555 

12.429 

12.305 

12.184 

12.065 

"•945 

11.834 

11.723 

34 

12.579 

12-453 

12.329 

12.208 

12.088 

11.972 

11.857 

"•745 

35 

12.611 

12.484 

12.360 

12.239 

12.119 

12.002 

n.888 

"•775 

36 

12.636 

12.508 

12.384 

12.262 

12.142 

12.025 

11.910 

11.797 

11 

39 

12.659 

12.691 
12.716 

12-53° 
12.564 
12.587 

12.407 
12.439 
12.462 

12.285 
12.316 
12.340 

12.165 
12.196 
12.219 

12.048 
12.078 
12.101 

"•933 
11.963 
11.986 

11.820 
11.850 
11.872 

4^ 

12.739 

12.611 

12.486 

12.363  ||  12.242 

12.124     12.008 

11.894 

Ammonia  Refrigeration. 

TABLE    V.— Continued. 


129 


<u 

II 

e  o 
H 

POUNDS  PER  SQUARE  INCH  ABSOLUTE  PRESSURE. 

27 

27^ 

27^ 

27^    ||      28 

28  # 

28  K 

28% 

Volume  in  Cubic  Feet  of  One  Pound  Weight  of  Gas. 

o 

10.797 

10.697 

10.598 

10.501 

10.406 

10.313 

IO.22I 

10.130 

i 

10.819 

10.719 

IO.62O 

10.523! 

10.428 

10-334 

IO.242 

10.151 

2 

10.849 

10.748 

10.650 

10.552 

10.456 

10.362 

10.270 

10.179 

3 

10.872 

10.770 

10.671 

10.573      10.477 

10.383 

10.291 

IO.20O 

4 

10.894 

10.792 

10.693 

10.595   |  10.499 

10.405 

10.312 

10.221 

10.923 

IO.822 

10.722 

10.624  < 

10.527 

10-433 

10.340 

10.249 

6 

10.946 

10.844 

10.744 

10.645  i 

10.549 

10.454 

10.361 

IO.27O 

7 

10.964 

10.866 

10.766 

10.667  j 

10.570 

10-475 

10.382 

10.290 

8 

10.997 

10.895 

10-795 

10.696  l 

10.599 

10.504 

IO.41O 

10.318 

9 

11.019 

10.917 

10.816 

10.717' 

10.620 

10.525 

10.431 

10.340 

10 

1  1.042 

10.939 

10.838 

IO-739! 

10.642 

10.546 

10.452 

10.360 

ii 

11.071 

10.968 

10.868 

10.768 

10.670 

10.578 

10.480 

10.388 

12 

11.094 

10.990 

10.889 

10.789! 

10.692 

10.596 

10.501 

10.409 

13 

11.110 

II.  012 

10.911 

10.811 

10.713 

IO.6I7 

10.522 

10.430 

H 

11.145 

II.O42 

10.940 

10.840 

10.742 

10.645 

10.551 

10-457 

15 

11.167 

11.064 

10.962 

10.862  | 

10.763 

10.666 

10.572 

10.478 

16 

11.190 

1  1.  086 

10.984 

10.883  ; 

10.785 

10.688 

10-593 

10.499 

'7 

11.219 

II.II5 

11.013 

10.912  | 

10.813 

10.716 

IO-62I 

10.527 

18 

11.242 

11.137 

"•°35 

10.9341 

10.835 

10-737 

10-642 

10.548 

'9 

11.264 

11.160 

11.056 

'0-955  ' 

10.859 

10-759 

10.663 

10.569 

20 

11.294 

11.189 

11.085 

10.984  | 

10.885 

10.787 

10.691 

10.596 

21 

11.316 

II.  211 

11.107 

1  1.  006 

10.906 

10.808 

10.712 

10.617 

22 
23 

II-338 
11.367 

"•233 

11.262 

11.129 
11.158 

11.027  i 
11.056 

10.927 
10.956 

10.830 
10.858 

10-733 
10.761 

10.638 

10.666 

24 

11.390 

11.284 

11.180 

11.078! 

10.977 

10.879 

10.  782 

10.687 

25 

11.412 

11.306 

1  1.  202 

11.099 

10.999 

10.900 

10.803 

10.708 

26 

11.442 

"•335 

11.231 

11.128 

11.027 

10.928 

10.831 

10.736 

27 

11.464 

".356 

"•253 

11.150 

11.049 

10.950 

10.852 

10.756 

28 

11.486 

"•379 

11.275 

11.171 

11.070 

10.971 

10.873 

10.777 

29 

11.516 

11.405 

11.308 

11.200 

11.099 

10.999 

IO.9OI 

10.805 

30 

"•538 

11.431 

"•325 

I  1.222  ! 

11.120 

1  1.  021 

10.922 

10.826 

3i 

1  1  .  560 

"•453 

"•347 

JI.244J 

11.142 

II.O42 

10.944 

10.847 

32 

1  1  .  590 

11.482 

11.376 

11.272 

1  1  .  1  70 

11.070 

10.972 

10.875 

33 

11.612 

11.504 

11.398 

II.  294  i 

11.192 

Il.Ogi 

10.993 

10.896 

34 

11.634 

11.526 

11.420 

II.3I6 

11.213 

II.II3 

11.013 

10.916 

35 

11.664 

"•556 

11.449 

"•345! 

11.242 

II.I4I 

II.O42 

10.944 

36 

n.686 

"•577 

11.461 

11.366! 

11.263 

II.I62 

11.063 

10.965 

37 

11.709 

1  1.  600 

"•493 

11.388! 

11.285 

II.I83 

11.084 

10.986 

38 

11.738 

11.623 

11.522 

11.417 

"•313 

II.  212 

II.  112 

11.014 

39 

1  1  .  760 

11.651 

"•544 

11.438     11.335 

"•233 

"•133 

11-035 

4^ 

11.783!  11.673    11.565  !  11.460'  11.363    11.254    11.154    11.056 

130 


Theoretical  and  Practical 
TABLE    V '.  —  Continued. 


POUNDS  PER  SQUARE  INCH  ABSOLUTE  PRESSURE. 


1^ 

«fc 

Ho 

29 

29  J< 

29  K 

29  K 

c  ^ 

29 

29^ 

29l/2        29% 

Volume  in  Cubic  Feet  of  One  Pound  Weight  of  Gas. 

O 

10.042 

9-955 

9.869 

9.785 

21 

10.524 

10-433 

10-343 

10.255 

I 

IO.002 

9-975 

9.889 

9.805        22 

10.545 

10.454 

10.364 

10.275 

2 

10.090 

10.003 

9-9I5 

9.832 

23 

10.573 

10.481 

10.391 

10.302 

3 

IO.  Ill    IO.O23 

9-936 

9.852 

24 

10-593 

10.502    10.411 

16.322 

4 

10.131    10.044 

9.872 

25 

10.611 

10.522    10.432 

10-343 

5 

10.159    10.071 

9.984 

9.899 

26 

10.642 

10.549    10.459    10.369 

6 

IO.I79    10.091 

10.004 

9.919 

27    10.662 

10.570  10.479;  IO-39° 

7 

10.2001  10.  112 

10.025 

9-939 

28 

10.683 

10.590  10.499  10.410 

8 

10.228   10.  139 

10.052 

9.966 

29 

10.711 

10.618  10.526 

10-437 

9 

10.249  10.  160 

10.072 

9.986 

30 

10.731 

10.638  10.547 

10-457 

IO 

10.269  10.  180 

10.093 

10.006 

31 

10.752 

10.659  10.567  10.477 

ii 

10.297 

10.208 

IO.  I2O 

10.033 

32 

10.779 

10.686 

10.594    10.504 

12 

10.318,  10.228 

IO.I4O 

10.053 

33 

10.800 

10.707 

IO.OI5    10.524 

!3 

10.338  10.249 

10.  160 

10.074 

34 

10.821 

10.727  10.635  10.544 

10.366  10.276 

10.188 

IO.  IOI 

35 

10.848 

10.755   10.662;  10.571 

15 

16 

10.386 
10.407 

10.296 
10.317 

10.208 
10.228 

10.  121 

IO.I4I 

36 

37 

10.869 
10.890 

10-775 
10.796 

10.682 
10.703 

10.501 
I0.6II 

17 

10-435 

10.344 

10.255 

IO.I68 

38   10.918 

10.823 

10.730 

10.638 

18 

10.455 

10.365 

10.276 

10.188 

39  i  10.938 

16.843 

10.750 

10.658 

19 

10.476 

10.385 

10.296 

IO.2O8 

40    10.959 

10.864  10.770 

10.679 

20 

10.504 

10.413 

10.323 

I0.235 

Ammonia  Refrigeration. 
TABLE  VI. 


jj 

!i 

E  o 
tn 

POUNDS  TER  SQUARE  INCH  ABSOLUTE  PRESSURE. 

so 

30J/C    |      30K 

30;^  ||    si 

31  J£ 

31  M 

31  K 

Volume  in  Cubic  Feet  of  One  Pound  Weight  of  Gas. 

o       9.701      9.620     9.540     9.461       9.374 

9-307 

9.232  ! 

9-J59 

I 

9.722      9.640;     9.560       9.481         9-4O3 

9-327 

9.25I 

9.178 

2 

9.748      9.6661     9.586       9.5071      9.429 

9-352 

9-277 

9.203 

3 

9.768      9.686      9.606 

9-527        9-448 

9-371 

9.296 

9-222 

4 

9.788'    9.706!    9.625     9.546      9-468 

9-391 

9-3J5 

9.241 

9-813     9-733i    9-651      9-572      9-493 

9.416 

9-340 

9.266 

6 

9-835     9-752     9-671      9-591       9-5I3 

9-436 

9-359 

9.285 

7 

9-855     9-772     9.691 

9.6ll         9-532 

9-455 

9-378 

9-3°4 

8       9.882     9.799     9.717 

9-637        9-558 

9.480 

9-404 

9-329 

9       9.902      9.818     9.737 

9-657 

9-58I 

9-499 

9-423 

9.348 

10      10.921      9.838 

9-756 

9.676 

9-597 

9-5J9 

9-442  ! 

9-367 

ii      10.948      9.865     9.883 

9.702 

9.622 

9-540 

9.467, 

9-392 

12          9.968       9.885       9.802;     9.722 

9.642 

9-564 

0.486 

9.4II 

13          9.988        9.904       9.822        9.741          9.661 

9-583 

9-505 

9-43° 

14        10.015        9.93I        9.848        9.767         9.687 

9.604 

9-531 

9-455 

ic;       10.035       9.951      9.868      9.787        9.706 

9.628 

9-550 

9-474 

16      10.055      9-971      9-888  S    9.806       9.726 

9.647 

9-569 

9-493 

17     10.082      9.997     9.914!    9.832       9.752 

9.672 

6-594 

9.518 

18      10.  102 

10.017     9-933     9-«52      9-771 

9.691 

9.613 

9-537 

19       10.122 

'0.037     9.953     9.871       9.790 

9.711 

9-632 

9-555 

20       10.148 

10.063     9-979  '    9-897       9.816 

9-736 

9.658 

9.581 

21        IO.I68 

10.083     9-999 

9-9I7        9-835 

9-756 

9.677 

9-599 

22        IO.I88 

10.103    Io-°i9 

9-936  •      9-855 

9-775 

9-696 

9.619 

23        IO.2I5 

10.  129 

10.045 

9.962 

9.881 

9.800 

9.721 

9.644 

24       10.235 

10.149 

10.065 

9.982 

9.900 

9.819 

9-  740 

9-663 

25        10.255 

10.  169 

i  o.  084 

IO.OOI 

9.919 

9-839 

9-759 

9.682 

26       IO.282 

10.195 

10.110 

10.027 

9-945 

9.864 

9-  785 

9-707 

27       10.301 

10.215 

10.  130 

10.047 

9.964 

9.884 

9.804 

9.726 

28       IO.322 

10-235 

10.  150 

10.066 

9-985 

9-9°3 

9-823. 

9-745 

29       10.348 

IO.2bl 

10.176 

10.092 

10.010  1    9.928 

9.848 

9-769 

30 

10.368 

I0.28I 

10.196 

IO.II2 

10.029      9.948 

9-867 

31 

10.388 

10.301 

10.215 

IO.I3I 

10.048 

9.967 

9.886 

9.808 

32 

10.415 

10.328 

10.242 

10.157 

10.074 

9.992 

9.912 

9-833 

33 

io-435 

10-347 

10.261 

10.177 

10.094 

IO.OII 

9-931 

9.852 

34 

10.455 

10.367 

10.281 

10.196 

10.113 

10.031 

9-95° 

9.870 

35 

10.482 

10.394 

10.307 

10.222 

10.139 

10.056 

9-975 

9.899 

36 

10.502 

10.413 

10.327 

IO.242 

10.158 

10.076 

9-994 

9.9I5 

37 

10.522 

10-433 

10.347 

I0.26I 

10.179 

10.095 

10.013 

9-934 

38 

10.548 

10.460 

10.373 

IO.288       IO.2O3 

IO.  I2O 

10.039 

9-959 

39 

10.568 

10.480 

10.392 

10.307 

10.219 

10.139 

10.058 

9.978 

40 

10.588    10.499    10.412    10.327     10.242 

10.159 

10.077 

9.996 

132 


Theoretical  and  Practical 

TABLE   V I .  —  Con  tin  ued. 


i' 
'£. 

POUNDS  PER  SQUARE  INCH  ABSOLUTE  PRESSURE. 

32 

32^ 

32  X 

32K     ||      33 

33  ft     |     33  K 

33  *•{ 

Volume  in  Cubic  Feet  of  One  Pound  Weight  of  Gas. 

o]  9.085 

9-014; 

8.944       8.874 

8.806 

8-739 

8.672 

8.607 

i    9.105  !  19.033 

.8.962        8.893 

8.824 

8-757 

8.690 

8.625 

2      9.129- 

9.058   !    8.987       8.917 

8.848 

8.781 

8.714- 

8.649 

3    9.148     9.076  '  9.005 

8.936 

8.868 

8.798 

8-732 

8.666 

4     9.167      9.095  •'   9.024 

8-954 

8.885 

8.817 

8.750 

8.684 

5    9.192     9.120     9.048 

8.978 

8.909 

8.841 

8.774 

8.708 

6    9.211  \  9.138     9.067 

8-997 

8-927 

8.859 

8.792 

8.726 

7;  9-229 

9.157   :    9.085 

9.015 

8.946 

8.877 

8.810 

8-743 

8    9-255 

9.182       g.IIO 

9-039 

8.969 

8.901 

8.834 

8.767 

9    9-273 

9-200       9.128 

9.058 

8.988 

8.919 

8.852 

8-785 

10 

9.292 

9.219       9.147       9.076 

9.006 

8-937 

8.870 

8.803 

ii 

9.3*7 

9.244       9.171        9.100 

9.030 

8.961 

8-893 

8.826 

'12 

9-339 

9.262       9.190 

9.119 

9.048 

8-979 

8.911  .• 

8.844 

13      9-355- 

"9.281       9.208 

9.I39 

9.066 

8.997 

8.929 

8.882 

14 

9-379 

9-306       9-233 

9.162 

9.091 

9.021 

8-953 

8.886 

15 

9-399 

9.324       9.251 

9.180 

9.109 

9.039 

8.971 

8.903 

*6 

9.417 

9-343      9-270 

9.198     9.127 

9.057 

8.989 

8.921 

IT 

9-442 

9-368 

9.294 

9.223      9.151 

9.081 

9.013 

8-945 

15  ! 

9-46i 

9.386:    9.313 

9.241      9.169 

9.099 

9.031 

8.963 

I«,       9.479 

9-405      9-331 

9.259   |  9.188 

9.118 

9.049 

8.980 

20  [  9-5°5 

9.430  |  9.356 

9.283      9.212 

9.142 

9-072 

9.904 

21       9.523 

9-449      9-374 

9-3°3    i  9-230 

9.160 

9.090 

9.022 

22       9.542 

9.467      9.393 

9.321      9.249 

9.178 

9.108 

9.040 

23      9-567 

9.492 

9.417 

9-345 

9-273 

9.202 

0.132 

9.063 

24      9.586 

9-501 

9-436 

9.363     9.293 

9.220 

9.150 

9.081 

\l 

9.605 
9.629 

9.529 
9-554 

9-454 
9-479 

9.381    i  9.309 
9-406     9-333 

9-238 
9.262 

9.168 
9.192 

9.099 
9.123 

27 

9.648- 

9-572 

"9-497 

9-424     9-351 

9.280 

9.210 

9.140 

2.8 

9-667 

9-591 

9.516 

9-443  | 

9-369 

9.298 

9.228 

9-158 

29 

9-692 

9.616 

9-541 

9.467 

9-394 

9-322 

9.252 

9.182 

3<? 

9-7M 

9-634. 

9-559 

9-485 

9.412 

9-340 

9.269 

9.199 

1-J 

9-729 

9.653 

9-577 

9-503 

9-43° 

9.358 

9.287 

9.217 

32 

9-755 

9.678 

9.602 

9-454 

9.382 

9-311 

9.241 

33 

9-773 

9.696 

9.621 

9.546     9.473 

9.400 

9-329 

9-259 

34 

9.792 

9.7I5 

9-639 

9.565      9.491 

9-418 

9-347 

9.277 

35 

9-817 

9.740 

9.664      9.589     9.515 

9-442 

9-371 

9.300 

36 

9.836 

9.682      9.607     9.533 

9.460 

9-3«9 

9-3!9 

37 

9.855 

9-777 

9.701    |  9.626 

9-552 

9-479 

9.407 

9-336 

38 

9.880 

9.802 

9.725 

9.650 

9-576 

9-5°3 

9-431 

9.360 

39 

9.898 

9.820 

9-744 

9.668 

9-594 

9.521 

9-449 

9-377 

40 

9.917      9.839      9.762       <;.687      9.612 

9-539      9-467      9-395 

Ammonia  Refrigeration.                     133 

TABLE  VI.—  Continued.   .___ 

2  c 

POUNDS  PER  SQUARE  INCH  ABsdLUTjeJPjR.EssuRE.     .    • 

II 

34 

34%     1     34^ 

34%     II      35      I-  '-35~!£-4-  35^- 

.35.3-^ 

So 

1 

'  1                               .  I-                                    1 

*'' 

H 

Volume  in  Cubic  Feet  of  One  Pound-W«ight-«f~€kis.  -  — 

o 

8-544 

8-479 

8.417 

8-355 

8.294 

8-235 

8'.  1  76      8.  1  1  7 

I 

8.561 

8-497 

8-434 

8-373  i 

8.312 

8.252 

8.193  :  8.134. 

2 

8.584 

8.520     8.458 

8-396   ; 

8-334 

8-275 

8.215     8.156. 

3 

8.602 

8.538 

8.475 

8.413 

8.352 

8.292 

8.232    8.173 

4 

8.619 

8-555 

8.492 

8.430 

8.369 

8.309 

8.249     8.193 

5 

8.644 

8-579 

8.516 

8-453 

8.391 

8-331 

8.271       8.212 

6 

8.661 

8.596 

8-533 

8.471 

8.409 

8.348 

8.288      8.229 

7 

8.676 

8.614 

8.550 

8.488 

8.426 

2-365  . 

8.305 

8.246 

8 

8.702 

8.637 

8.574 

8.511 

8.449 

8.388 

-8,327-  ::£:268. 

9 

10 

8.719 
8.738 

8-654 
8.672 

8.608 

8.528 
8-545 

8.466 
8.483 

8.405 
8.422 

8.344; 
8,361 

:&28$ 

8,302;  i 

H 

8.761 

8.695 

8.632 

8.568 

8.506 

S-445 

8.384         8;  32  7.; 

12 

8-779 

8-713 

8.649 

8.586 

8-523 

8.461 

8,401          8.341 

J3 

f'P6 

8.730 

8.666 

8.603 

8.540 

8-471 

8,418..       8,358... 

8.819 

8-754 

8.690 

8.626  ! 

8.563 

8.501  . 

8,440           8;  3§0  :  • 

15 

8.838 

8.771 

8.707 

8.643 

8.580 

8-519  . 

8-457           8.397 

16 

8-855 

8.789 

8.724 

8.660 

8-597 

8.536 

8.474           8.414 

17 

8.879  i  8.811 

8.748      8.683 

8.620 

8.556 

8.496           8.436 

18 
19 

8.896 
8-913 

8.830 
8.847 

8.765      8.701       8.637 
8.782       8.718  !    8.655 

8-575 
8.592 

8.513     >      8.453 
8.530           8-470 

20 

8.938 

8.871 

8.806       8.741   j 

8-677 

8.615 

8.553           8.492 

21 

8-955 

8.888 

8.823 

8.758 

8.694 

8.632 

8.570 

8.509 

22 
23 

8-973 
8.996 

8.906 
8.929 

8.840 
8.863 

8-776  i 
8.798 

8.712 
8-735 

8.649 
8.672  - 

8.587 
8.609   - 

8.526 

24  '    9.014 

8-947 

8.  88  1 

8.816 

8.752 

8.689 

8.626 

g  565  ' 

25      9.032 

26    9.055 

8.964 
8.990 

8.899 
8.922 

8-833 
8.856  ! 

8.769 
8.792 

8.706 
8-729 

.8.643 
8.674 

8.582  • 
8.604^. 

27      9-073 

9.005 

8.940 

8.873 

8.809 

&74S 

.8.682 

8.621 

28      9.090 

9.022 

8.956      8,891   i    8.826 

8.762 

8.699 

8.638; 

29 

9.114 

9.046      8.980  !    8.914  ||   8.849 

8.788  - 

8.722 

8.660 

30 

9.132 

9.063      8.997      8.931   i    8.866 

8.802 

8-739 

8.677 

31       9.149 

9.081  •  9.014      8.948  ,    8.883 

8.819 

8.756 

8.693 

32      9.  I  70 

9.104  1  9.037      8.971       8.906 

8.842 

8-778 

8.716 

33      9.190    :    9.122       0.055         8.988         ^.923 

8.859      8.795 

8-733 

34    9.209     9.139      9.072      9.006       8.940 

8.876 

8.812 

8-749 

35  '  9.232     9.163     9.095  ;   9.029  l    8.962 

8.899 

8.834 

8.772 

36:9.249     9.177     9.113      9.046       8.980 

8.916 

8.85! 

8.789 

37    9-267     9.198     9.130      9.063       8.997 

8-933 

8.868 

8.805     , 

38    9.290     9.221      9.153      9.086  ||  9.020. 

8^955 

8.891 

8.828     " 

39    9.308 

9.239     9.171   !   9.104      9.037 

8-972 

8.908 

8.845 

40    9.326 

9.262     9.188      9.124      9.055      8.989 

8.925 

8.861 

134                   Theoretical  and  Practical 

TABLE  VI.—  Continued. 

rt  J; 

POUNDS  PER  SQUARE  INCH  ABSOLUTE  PRESSURE. 

c6  -••)     36% 

36^ 

36K    ||      37 

37  X 

37  X 

37  <4 

£                       Volume  in  Cubic  Feet  of  One  Pound  Weight  of  Gas. 

o      8-.o6i    ;  '8.003 

7.948       7.893 

7.839 

7.785 

7-732 

7.680 

I       8.077    i    8.020 

7-909    ,   7-855 

7.801 

7.748 

7.696 

2       8.099       8.042 

7^986 

7-931        7-877 

7.823 

7.769 

7.717 

3      8.  116  \   8.059 

8.005 

7-947      7-893 

7.839 

7.785 

7-733 

4      8.133      8.075 

8.019 

7-963 

7.909 

7.855 

7.801 

7-749 

5  !  8.155 

8.097 

8.041 

7-985 

'  7-931 

7.871 

7.823 

7.770 

6      8.172 

8.114 

8.057 

8.001 

!  7-947 

7.892 

7.839 

7.786 

7 

8.188 

8.130 

8.074 

8.018 

I  7-963 

7.908 

7.855 

7.801 

8      8.2ii 

8.152 

8.096 

8.040 

7.985 

7-93° 

7.876 

7-823 

9      8.227 

8.169 

8.  1  12 

8.056 

8.001 

7.946 

7.892 

7-839 

10      8.244 

8.185 

8.129 

8.072   |  8.017 

7.962 

7.908 

7-855 

ii 

8.266 

8.208 

8.150 

8.094 

8.039 

7.984 

7.929 

7.876 

12 

8.283 

8.227 

8.167 

8.  1  10 

1  8.055 

8.000 

7-945 

7.892 

13 

H 

8.299 
8.322 

8-243 
8.263 

8.183 
8.205 

8.127 
8.148 

8.071 
8.093 

8.016 
8.037 

7.961 
7-983 

7.908 
7.929 

15 

8.338      8.279 

8.222 

8.165 

8.109 

8-053 

7-999 

7-945 

1  6 

8-355 

8.296 

8.238     8.181 

8.125 

8.070 

8.017 

7.961 

17 

8-377 

8.318 

8.260 

8.207 

8.147 

8.091 

8.036 

7.982 

18 

8.394 

8-334 

8.276     8.219 

8.163 

8.107 

8.049 

7.998 

19 

8.410 

8-351 

8.293     8.235    !  8-179 

8-123 

8.068 

8.014 

20 

8-433 

8-373 

8.315      8.251      8.201 

8.145 

8.089 

8.035 

21 

8-449 

8.390 

8.331    !  8.274  :    8.217 

8.161 

8.105 

8.051 

22 

8.466 

8.406 

8.348 

8.290 

8.234 

8.177 

8.I2I 

8.067 

23 

8.488 

8.428 

8.370 

8.312 

8-255 

8.198 

8-139 

8.088 

24 

8-505 

8-445 

8.386 

8.328 

8.271 

8.215 

8.159 

8.104 

25 

8.521 

8.461 

8.403 

8.344   1  8.288 

8.231 

8.172 

8.  12O 

26 

8-544 

8.483 

8.424 

8.366  :   8.309 

8.252 

8.196 

8.141 

27 

8.561 

8.500 

8.441 

8.383  i    8.325 

8.268 

8.212 

8.157 

28 

8-573 

8.516 

8-457 

8.399      8.342 

8.286 

8.228 

8.173 

29 

8-599 

8-539 

8.479 

8.420      8.363 

8.306 

8.249 

8.194 

30 

8.616 

8-555 

8.496 

8-437      8.379 

8-322 

8.265 

8.210 

8-633 

8-572 

8.512 

8.453      8.407 

8.338 

8.281 

8.226 

32 

8-655 

8-594 

8-534 

8-475      8.417 

8.360 

8.303 

8.247 

33 

8.672 

8.610 

8-550 

8.491    |  8.434 

8.376 

8.319 

8.263 

34 

8.688 

8.626 

8-567 

8.508 

8.449 

8.392 

8-337 

8.279 

35 

8.711 

8.649 

8.589 

8.529 

8.471 

8.413 

8-356 

8.300 

36 

8-727 

8.638 

8.605 

8.546 

8.488 

8.429 

8.372 

8.316 

% 

8-744 
8.766 

8.654 
8.704 

8.622 
8.644 

8.562 
8.584 

8.504 
8.525 

8-445 
8.467 

8.388 
8.409 

8.332 

8-353 

39      8.783 

8.721 

8.660 

8.600 

8.542 

8.483 

3.422 

8.369 

£  o      S.  7QQ 

8-737 

8.676      8.616      8.558 

8.499 

8.441 

8-385 

Ammonia  Refrigeration. 
TABLE   VI.— Continued. 


135 


g 

3      . 
|° 

POUNDS  PER  SQUARE  IXCH  ABSOLUTE  PRESSURE. 

38 

38  % 

ss  y2 

38%     ||      39 

39  # 

29  K     |    39  ^ 

Volume 

in  Cubic  Feet  of  One  Pound  Weight  of  G-as. 

O 

7.629 

7.578 

7.528 

7.478 

7-43° 

7-38I 

7-334 

7-287 

I 

7.645 

7-593 

7-543 

7-494 

7-446 

7-397 

7-349 

7.302 

2 

7.666 

7.614 

7-564 

7-5I5 

7.466  |   7.417 

7-369 

7.322 

3     7.682 

7.630 

7-580 

7-53° 

7.482 

7-432 

7-385 

7-337 

4 

7.698 

7.646 

7-595 

7-546 

7-497 

7.448 

7.400 

7-352 

5 

7.719 

7-667 

7.616 

7-566  ; 

7-5l6 

7.468 

7-421 

7-375 

0 

7-734 

7.682 

7.632 

7-582  | 

7-533      7-483 

7-435 

7-388 

7 

7-75° 

7-698 

7.647 

7-597  1 

7-548  ;   7.499 

7-45° 

7-403 

8 
9 

7.771 
7-787 

7.719 

7-735 

7.668 
7.684 

7.618 
7.628  i 

7-569  i   7.519 
7-584  i   7-534 

7-471 
7.486 

7-423 
7.438 

10 

7.803 

7-75° 

7-699 

7-649   |  7-599  ;   7-55° 

7-501 

7-453 

1  1 

7.824 

7.771 

7.720 

7.669      7.620      7.570 

7-521 

7-473 

12 

7-839 

7.787 

7-685    i  7-635 

7.585 

7.536 

7.488 

13 

7-85° 

7-803 

7-751 

7.700  !    7.651 

7.601 

7.552 

7-5°3 

14 

7.877 

7-824 

7.772 

7.721 

7.671 

7.621 

7-572 

7-524 

15 

7.892 

7-839 

7-788 

7-737 

7.686 

7.636 

7.587 

7-539 

16 

7.908 

7.855 

7.803 

7-752 

7.702 

7.657 

7.602 

7-554 

»7 

7.929 

7.875 

7.824 

7-723 

7.672 

7-623 

7-574 

18 

7-945 

7.892 

7.840 

7.788 

7-738 

7-687 

7-638 

7-589 

19 

7.961 

7-907 

7.855 

7.804 

7-753 

7.702 

7-655 

7.604 

20 

7.982 

7.928 

7-876 

7.824 

7-774 

7.723 

7-673 

7.624 

21 

7.998 

7-944 

7.891 

7.840      7.789 

7.738 

7.688 

7-639 

22 

8.013 

7.960 

7.907 

7.855      7-805 

7-753 

7.704 

7-654 

23 

8.034 

7.980 

7.928 

7.876      7.825 

7-774 

7-724 

7-674 

24 

8.050 

7.996 

7-943 

7.891       7.841 

7.789 

7-739 

7.690 

25 

8.066 

8.012 

7-959 

7.907      7.856 

7.804 

7-754 

7.702 

26 

8.087 

8.033 

7-98o 

7.928 

7.876 

7-825 

7-774 

7.725 

27 

,  8.103 

8.048 

7-995 

7-943  i 

7.892 

7.840 

7.790 

7.740 

28 

8.  1  19 

'  8.064 

8.0H 

7-956 

7.907 

7.855 

7-805 

7-755 

29 

8.139 

8.085 

8.032 

7.979  jj  7.928      7.876 

7.825 

7-775 

3° 

i  8.101 

8.047 

7-995       7-943   !   7-891 

7.840 

7.790 

31 

8.  i  71 

8.  in 

8.063  '  8.010    •  7-958      7.906 

7.855      7.805 

32 

8.192 

1  8.137 

8.084     8.031       7.979  !   7.927 

7.876      7.826 

33 

8.208 

i  8.153 

8.099     8.046      7.994      7.942 

7.891 

7.841 

34 

8.224 

j  8.169 

8.115 

8.062      8.009  i   7-955      7-9o6 

7.856 

35 

8.245 

8.190 

8.136 

8.082      8.030      7.978      7.926      7.876 

36 

8.261 

8.205 

8.151 

8.097      8.046  !   7.993 

7.942      7.891 

37 

8.277 

8.221 

8.167     8.113      8.061    i  8.008      7.957      7.906 

38 

8.298 

8.242 

8.188     8.134      8.082   :  8.029      7.977      7.926 

39 

,  8.313 

8.258 

8.203      8.149      8.097      8.044      7.992      7.941 

40  I  8.329 

8.273 

8.219     8.165      8.113      8.059      8.007      7-956 

136 


Theoretical  and  Practical 
TABLE   VI.— Continued. 


i 

Ij3 

SI 

0  ° 

POUNDS  PER  SQUARE  INCH  ABSOLUTE  PRESSURE. 

40 

40#    |    40K 

40  X    ||      41 

41  X 

41  M 

41% 

Volume  in  Cubic  Feet  of  One  Pound  Weight  of  Gas. 

o 

7.241    '    7.193 

7.125      7.105 

!  7.061  !  7.017    6.974 

6.932 

I 

7.256 

7.201 

7.164 

7-I2O 

7.076    7.032 

6.989 

6.946 

2 

7.276 

7.230 

7.184 

7.139  j     7.096       7.051 

7.008 

6.966 

3 

7.291 

7.245 

7.199 

7.154       7.IIO 

7.066 

7.023 

6.980 

4 

7.306 

7.260 

7.214 

7-  *69 

7-125 

7.080 

7.037 

6-995 

5 

7.326 

7.280 

7-234 

7.188 

7.144 

7-IOO 

7.056 

7-013 

6 

7-341 

7.294 

7-243 

7.203 

7.159 

7.II4 

7.071 

7.028 

7 

7-356 

7-3c9 

7-263 

7.218 

7-174 

7.129 

7.085 

7.042 

8 

7-376 

7-329 

7-283 

7.238 

7.193 

7.148 

7.105 

7.061 

9 

7-391 

7-344 

7.298 

7.252 

7.208 

7.163 

7.119 

7.076 

10 

7.406 

7-359 

7-313 

7.267 

7.222 

7.177 

7.134 

7.090 

ii 

7.426 

7-379 

7-332 

7.287 

7.242 

7.197 

7.153 

7.109 

12 

7.441 

7-394 

7-347 

7.301    i  7.257 

7.211 

7.167 

7.124 

'3 

7-456 

7.409 

7.362 

7.316      7.271 

7.226 

7.182 

7-138 

14 

7.476 

7-429 

7-382 

7-336 

7.291 

7.245 

7.201 

7-157 

15 

7.491 

7-443 

7-397 

7-350 

7.305 

7.260 

7.215 

7.172 

16 

7.506 

7.458 

7.411 

7-365 

7.320 

7.274 

7.230 

7.186 

'7 

7.526 

7.478 

7-431 

7-385 

7-339      7.294 

7.249 

7.205 

18 

7-541 

7-493 

7-446 

7.400 

7-354 

7.308 

7.264 

7.219 

19 

7.556  !   7.508 

7.461 

7.414 

7.369      7.323 

7.278 

7-234 

20 

7.576 

7.528 

7.480 

7-434 

,  7-388 

7.342 

7.297 

7-253 

21 

7-590 

7-543 

7-495 

7-449 

!  7-403      7-357 

7.312 

7.267 

22 

7.558 

7-510 

7.463      7.418      7-371 

7.326 

7.282 

23 
24 

7.620 
7.641 

7-578 
7-593 

7-53° 
7-541 

7-483 
7.498 

7-437      7-391 
7.452      7.405 

7.346 

7-3°° 

7-301 
7-3!5 

7.656 

7.607 

7.560 

7-512 

7.466      7.420 

7-374 

7-33° 

26        7.676 

7.627 

7-579 

7.532      7.486      7.439 

7-394 

7-349 

27 

7.691 

7.642 

7-594 

7-547      7-5°o      7.454 

7.408 

7-363 

28 

7.710 

7.657 

7.561 

7.515      7.468 

7-423 

7-377 

29 

7.726 

7.677 

7.629 

7.581 

7-535      7.488 

7.442 

7-397 

30 

7-741 

7.692 

7-643 

7.596      7-549      7-502 

7-456 

7-4H 

3i 

7.756 

7.707 

7.658 

7.611      7.564  ,  7.514 

7-471 

7-425 

32 

7.776 

7-727 

7-678 

7.630      7.583      7.536 

7.490 

7-445 

33 

7.791 

7.742 

7-693 

7.645      7.598  .   7.551 

7-505 

7-459 

34 

7.806 

7-757 

7.708 

7.660      7.613      7.565 

7-5T9 

7-473 

35 

7.826      7.776 

7.727  \  7.679      7.632      7.585 

7.538 

7.492 

36 

7.841       7.791 

7-742  \  7.694      7.647      7.599 

7-553 

7.507 

37 

7.856      7.806 

7-759     7-709      7-66i    j   7.614     7.567 

7-521 

38      7.876 

7.826 

7-777 

7.728      7.681      7.633      7.587 

7-54° 

39 

7:891       7.841      7.792      7.743      7.696      7.648      7.601 

7-555 

40      7.906      7.856     7.806     7.758      7.710      7.662      7.615 

7o69 

Ammonia  Refrigeration.                     137- 

TABLE  VI 

—  Continued. 

E 

3      . 

POUNDS  PER  SQUARE  INCH  ABSOLUTE  PRESSURE. 

?  -£- 
U.re 
P.* 

42 

42  Y4 

42  K 

42  # 

II     43 

43  y4 

43  % 

43^-; 

H 

Volume  in  Cubic  Feet  of 

One  Pound  Weight  of  Gas. 

o 

6.88<?       6.849       6.808 

6.767 

!    6.727 

6.688 

6.649 

6.610 

I    i  6.905  I    6.853      6.822 

6.781 

6.741 

6.701 

6.662 

6.623 

2    '    6.924        6.882        6.841         6.800 

.6.759       6.720 

6.681 

6.642 

3     6.9.18 

6.896       6.855 

6.814 

6-774  !   6-734 

6.694 

6.656 

4 

6.952 

6.911   ;    6.869 

6.828 

6.787     6.748 

6.708 

6.669 

5 

6.971      6.929      6.888 

6.847 

!     6.806  !    6.766 

6.727 

6.688 

0 

6.986     6.944      6.902 

6.861 

ii  6.820     6.780 

6.740 

6.701 

7 

7.000 

6.958 

6.916 

6.875 

6.834 

6-794 

6-754 

6-715 

8 

7.019 

6.977 

6-935 

6.894 

6.853 

6.812 

6.772 

6-733 

9 

7-033 

6.991 

6.949 

6.908 

6.867 

6.826 

6.786 

6-747 

10 

7.047 

7.005 

6.963 

6.922 

6.881 

6.842 

6.800 

6.761 

ii 

7.067 

7.024      6.982 

6.941 

i  6.899 

6.859 

6.819 

6-779 

12 

7.081 

7.038 

6.996 

6-955 

6.913 

6-873 

6.832 

6-793 

13 

7-095 

7-°53 

7.010 

6.969 

6.927 

6.886 

6.846 

6.806 

»4 

7.114 

7.071 

7.029 

6.987 

6.946 

6.905 

6.865 

6.825 

7.129 

7.086 

7-043 

7.001 

6-959 

6.919 

6.879 

6.838 

16 

7-143 

7.099 

/•057 

7-015 

:   6.974 

6-933 

6.892 

6.852 

'7 

7.162 

7.119 

7.076 

7-034 

6.992 

6.951 

6.910  . 

6.870 

18 

7.178 

7-133 

7.091 

7.048 

7.006 

6-965 

6.924 

6.884 

19 

7.190      7.147 

7.104 

7.062 

7.020 

6-979 

6.938 

6.898 

20 

7.209      7.167 

7-123 

7.081 

7-039 

6-997 

6-957 

6.916 

21 

7.224  '    7.180 

7-137 

7-095 

7.053 

7.011 

6.970 

6.930 

22        7.238        7.194 

7-151 

7.109 

7.066      7.025 

6.984 

6-944 

23 

7-253      7-2I3 

7.170 

7.128 

7.085  :  7.044 

7.002 

6.962 

24 

7.271      7.223 

7.184 

7.142 

7.099    7.058 

7.016 

6.976 

25 

7.286     7.242      7.199 

7-156 

7-113  i  7-071 

7.030 

6.989 

26 

7-305 

7.201       7.217 

7-175  ; 

7.132    7.090 

7.049 

7.008 

27 

7-3I9 

7-275       7-231       7.188 

7.146 

7.104 

7.062 

7.021 

28 

7-333 

7.289      7.246      7.203 

7.162 

7.118 

7.076 

7-035 

29 

7-352 

7.308       7.264      7.221 

7.178    7.136 

7.094 

7-053 

3« 

7.366 

7.322       7.279      7.235 

7.192    7.150 

7.108      7.067 

3i 

7-381 

7-33^      7-293      7-249 

7.206  1  7.164    7.122    7.081 

32 

7.400 

7-355      7-311      7-268 

7.225       7.182       7.140    !    7.099 

33 

7.414 

7.369      7.326      7.282 

7.239            7.196           7.154      :       7.II3 

34 

7.429 

7.384      7.340      7.296 

7.253            7.210           7.168             7.126 

35 

7.448 

7-403      7.358      7-315 

7.271             7.229 

7.186      7.145 

36 

7.462      7-417      7-373      7-329 

7.285             7.243 

7.200  j   7.158 

37 

7-476     7-431      7-3^7 

7-343 

7.299            7.256 

7.214      7.172 

38 

7-495 

7.450 

7.406 

7.362 

7.318            7.275 

7.232      7.190 

39 

7.509      7.464 

7.420 

7-376 

7-332 

7.289      7.246      7.204 

40     7.524      7.479 

7-434 

7-390 

7.346 

7.303      7.260      7.218 

138 


Theoretical  and  Practical 
TABLE   VI.— Continued. 


POUNDS  PER  SQUARE  INCH  ABSOLUTE  PRESSURE. 


44 


44 


44  tf 


45 


H                       Volume  in  Cubic  Feet  of  One  Pound  Weight  of  Gas. 

o           6.571             6.534             6.497            6.460 

6.423 

I               6.585 

6.548 

6.510             6.473 

6.436 

2               6.603 

6.566 

6.528 

6.491 

6-454 

3           6.617 

6-579 

6.542 

6.504 

6.467 

4 

6.631 

6.592 

6-555 

6.518 

6.481 

5 

6.649 

6.611 

6-573 

6.536 

6.498 

6 

6.663 

6.624 

6.587 

6-549 

6.512 

7 

6.676 

6.638 

6.600 

6-562 

6-525 

8 

6.694 

6.656 

6.618 

6.580 

6.543 

9 

6.708 

6.669 

6.631 

6-594 

6.556 

10 

6.722 

6.683 

6.645 

6.607 

6-569 

ii 

6-739 

6.701 

6.663 

6.625 

0.587 

12 

*3 

6-753 
6.767 

6.715 
6.728 

6.676 
6.690 

6.638 
6.652 

6.601. 

6.612 

H 

6.785 

6.746 

6.708 

6.669 

6.632 

15           6.799 

6.760 

6.721 

6.683 

6.652 

16           6.812 

6-773 

6-735 

6.697 

6.658 

17           6.831 

6.792 

6-753 

6.714 

6.676 

18 

6.844 

6.805 

6.766 

6.728 

6.689 

19 

6.858 

6.819 

6.781 

6.741 

6-703 

20 

6.876 

6.837 

6.798            6.759 

6.721 

21 

22 

6.889 
6.903 

6.850 
6.864 

6.811             6.772 
6.825             6.784 

6,734 
6-747 

23 

6.922 

6.882 

6.843            6.804 

6.765 

24 

6-933 

6.895 

6.856            6.817 

6.778 

25 

6.949 

6.909 

6.870            6.831 

6.792 

26 

6.967 

6.927 

6.880            6.848 

6.809 

27               6.981 

6.941 

6.901             6.862 

6.823 

28 

6-994 

6-954 

6.914            6.875 

6.836 

29 

7.012 

6.972 

6.932 

6.893 

6.854 

30 

7.026 

6.986 

6.946 

6.907 

6.867 

31 

7.040 

6-999 

6-959 

6.920 

6.881 

32 

7.058 

7.018 

6.978 

6-937 

6.898 

33 

7.072 

7.031 

6.991 

6.951 

6.912 

34 

7.085 

7-°45 

7.004 

6.965 

6.925 

35 

7-103 

7-063 

7.022 

6.982 

6-943 

36 

7.117 

7.076 

7.036 

6.996 

6.956 

37 

7-I3I 

7.090 

7.049 

7.009 

6.969 

38 

7.149 

7.108 

7.067 

7.027 

6.987 

39 
40 

7.163 
7.176 

7.122 

7-135 

7.081 
7.094 

7.041 
7-054 

7.001 

7.014 

Ammonia  Refrigeration.  139 


INDEX. 


PAGE 

ABSOLUTE  pressure       .             .             .             .  13 

,,           temperature         ...  13 

,,           zero                .              .              .              .  .16 

Air,   specific   heat  of,    by   Regnault's  determinations,          8 

,,           ,,                ,,         under  constant  pressure     .  7 

,,           ,,               ,,         with  constant  volume  .  .         9 

,,     theory  of  freezing  by  .             .             .  19 

Ammonia,   action  of,   on  copper,   etc.  .       25 

,,            amount  to  be  charged               .              .  5° 

,,            anhydrous,   apparatus    for  preparing  .      115 

,,                     ,,                    ,,            water  from         .  ill 

,,                     „             cost  of  preparing         .  114 

,,  ,,  effect  of  pressure  on   specific 

heat  of                       .  .7 

,,                     ,,             preparation   of        .  107 

,,                     ,,             yield  of  .      113 

,,            characteri.-,tics  of          .  22 

,,            circulated     ...             .             .  79,  98 

,,             comprc'-M-r,   clearance    space,   etc.  .        35 

,,                       ,,               Imri/ontal               .               .  31 

,,                      ,,              lubrication      .             ...  34.  35 

,,                     ,,             measurements  of  ga ,  .       79 

,,                     ,,             stuffing-boxes        .             .  32 


140  Index, 

PAGE 

Ammonia  compressor  valves  .  .  .  36 

,,  ,,  vertical  ...  31 

,,  condenser  .  .  .  .  .42 

,,  condensed,  loss  due  to  heating,  56,  102,  105 

,,  cooling  directly  by  .  .  65 

,,  difference  between  anhydrous  and  26°  .  25 

,,  gas,  loss  due  to  superheating  .  58,  103,  105 
,,  ,,  volume  of,  at  high  temperatures 

(Table  I.)  .  .  .  51 

,,.  ,,  volume  of,  at  high  temperatures 

(Tables  V.  and  VI.)  .  122  to  138 

,,  plant,  arrangement  of  .  26 

,,  ,,  charging  with  am:nonia  .  47,  49,  50 

,,  ,,  working  details  .  .  47 

,,  test  for  .  .  .  .  .in 

,,  theory  of  freezing  by  .  .  .  21 

BOILING-POINT  of  ammonia,  tables  of,  113,  116,  117 

Brine  .             .             .                           .             .  .66 

,,  choice  of                    .                          .             .  70 

,,  figures  for  calculating  capacity  of  plant  .       99 

,,  freezing-point  of                    .             .             .68,  69 

,,  making    .             .             .             .             .  71,  72 

,,  specific  heat  of         ....  73 

,,  strength  of                        .             .             .  .69 

,,  tank  or  refrigerator              ...  44 

,,  ,,      area  of  piping  in  .             .             .  .45 

,,  temperature,  affected  by  condensing  water,  77 

,,  ,,                regulation  of .             .             .  73,  75 

British  thermal  unit      .  .             .             .  .3 

CALCULATING  results  of  tests  of  refrigerating  plant, 

92  to  105 
,,  maximum  capacity  .  .  106 


Index.  141 

PAGE 

Characteristics  of  ammonia     .  .22 
Charging  an  ammonia  plant          .                        47»  49  to  51 
Chloride  of  calcium  brine        .             .             .  66  to  72 
Chloride  of  magnesium  brine        .             .             .  66 
,,            sodium       .             .             .             .  .66 
Compressed  air,  theory  of  freezing  by    .              .  19 
Compressor        .             .             .             .  •       31 
,,             clearance  space.  35 
,,            effect  of  well  jacketing   .  .       95 
,,            effectual  displacement  of       .             .  97 
,,             indicator  diagrams             .             .  88  to  91 
,,             jacket-water    ....  52 
,,            loss  in  well-jacketed        .             .  .80 
,,                  "       double-acting              .             .  So 
,,             measurements  of  ammonia  circulated,           79 
Condensed  ammonia,   loss  due  to  heating,        56,  IO2,  105 
Condenser  water      .....  53 
,,              .,       effect  on  brine   temperature  .        77 
,,              ,,       quantity  necessary          .              .  56 
.,              ,,       lessening  cost  of                   .  -54 
,,             ,,       worm       .                         .             .  42 
Condensing  pressure     .                          .  "59 
,,                 ,,         cause  of  variation  in  excess,          60 
,,                  ,,  use  of,  in  determin'g  loss  of  ammonia,   63 
Constant  pressure,   specific  heat  of  air  under  .           7 
,,          volume,  specific  heat  of  air  with          .  9 
Construction  details  of  ammonia  plant            .  .:       3° 
,,              of  anhydrous  ammonia  generating  ap- 
paratus      .             .             .              .  I 08,  115 
Cooling  directly  by  ammonia  .             .  -65 
,,         from  a  high  to  a  low  temperntu: ••-•          .  75 
Copper,  action  of  ammonia  on             .  -25 
Cost  of  preparing  anhydrous  ammonia    .              .  114 


142  Index. 

PAGE 

DEHYDRATOR,  lime  for  .          .  .  .  .112 

Details  of  ammonia  plant,  construction   .  .  30 

,,  ,,  ,,       working    .  .  -47 

Determining  refrigerating  efficiency  of  plant        .  78 

,,  ,,  ,,     by  ammonia  figures,     96 

,,  ,,  „          by  brine  figures,       99 

Diagrams,   indicator,   of  compressor    .  .          18  to  91 

Discharge  valve       .  .  *  ...  36 

Displacement  of  compressor,   effectual  .  .       97 

Distribution  of  mercury  wells.      .  .  .  81 

Duration  of  tests  of  ammonia  plants  .  -87 

EFFECT  of  composition  on  freezing-point  of  brine,       68 
,,  condensing  water  on  brine  temperature,        77 

,,  excessive  valve-lift      ...  37 

,,  pressure    on    specific  heat    of  ammonia,          7 

,,  ,,          and  temperature  on  volume  of 

ammonia  gas        .       51,  122  to  132 
,,  ,,  and  temperature  on  volume  of 

gases.  .  .  .16 

,,  strength  on  freezing-point  of  brine,  69 

,,  well-jacketed  compressors         .    .  .      .95 

Effectual  displacement  of  compressors     .  .  97 

Efficiency,   refrigerating  .  .  .  .98 

Equivalent  of  a  ton  of  ice  .  .  .        ,      79 

,,  ,,     unit  of  heat    .  .  ...  .         4 

Examination  of  working  parts       .  .86 

Excess  condensing  pressure     .  .  .  -59 

,,  ,,  ,,  cause  of  variations  in,         60 

Expansion  valves    .....  46 

FORMUL/E  for  calculating  volume  of  gases    .  .        16 

Freezing-point  of  brine      ....  68 


Index.  1 43 

PAGE 

Freezing-point  of  brine  affected  by  composition       .       68 
55  55  55  strength       .  69 

GAS,  ammonia,  heated  by  compression,  table  of  .  118 

,,  ,,  specific  heat  of  .  .  .  7 

,,  ,,  volume  of  .  .  .97 

,,  ,,  tables  of  volume  of  .  .  51,  122 

,,  ,,  loss  due  to  superheating  .  .  103 

Gases,  formulae  for  calculating  volume  of  .  16 

HEAT  terms       ......  3 

,,  latent,   of  ammonia,   table  of          .             .    116,  117 
,,               ,,           liquefaction    .             .             .             .10 

,,               ,,           vaporization         .              .              .     '  II 

,,               ,,           water               .             .             .     '         .  12 

,,  mechanical  equivalent  of     .             .             .  4 

,,  specific     .  .  .  .  .  -4 

55             55       affected  by  temperature  and  pressure,  6 

55             55       of  air                    .             .             .             .  7 

,,             55        55  ammonia  ras        ...  7 

55             55        55  brine  .             .             .             .             .  73 

,,             ,,       ,,  mercury    ....  5 

55  55  ,5  turpentine  .  .  .  "  '.  cj 

5>  55  51  water  .  .  .  .  5 

Horizontal  compressor               .             .             .             .  31 

ICE,   equivalent  of  a  ton  of  .             .              79 

Indicator  diagrams         .  .             .             .             -87 

55                 5»         used    in  calculating    capacity    of 

plant  .             .             .    92  to  95 

JACKET-WATER  for  compressor  .  .  52,  53 

,,  ,,    separator  .  .  53 


144  Index. 

PAGE 

Joule's  law         ......         4 

LATENT  heat           .....  10 

,,         heat  of  ammonia,  table  of    . .  ,  .          116,  117 

„               ,,        liquefaction           .             .  .              10 

„               „        vaporization  .             .  .             .11 

„              ,,        water        .             .             .  .              12 

Lime  for  dehydrator     .             .             .  .             .112 

Loss  due  to  heating  condensed  ammonia  .    102,  105 

,,           ,,       superheating  ammonia  gas  .          103,  105 

MAGNESIUM  chloride  brine            .  .            .             66 

Making  brine     .              .             .              .  .             .71 

Maximum  capacity  of  plant             .  .             .            106 

Measurement  of  ammonia  circulated  .  .             -79 

Mechanical  equivalent  of  a  unit  of  heat  *                4 

Mercury,  specific  heat  of                      .  .             .5 

,,  .       wells,  distribution  of     .  .             .              81 

,,             ,,       how  made        .             .  .          82  to  85 

OIL  for  lubrication  .  .  .  .  35 

PACKING  for  stuffing-boxes      .....       33 

Piping  (or  worm)  for  condenser                .  .              42 

,,        for  refrigerator               .             .             .  -45 

Preparation  of  anhydrous  ammonia          .  .             107 

,,                       ,,                     ',,           cost  of  .  .114 

Pressure,  absolute  .             .             .             .  .13 

,,.          effect  of,  On  specific  heat   .             .  6,  7,  16 

RECEIVER    .  .  .  .  .  .  43 

Refrigerating  efficiency  of  a  plant,   t">  determine      .        78 
.  .  •  •  98 


Index.  145 

PAGE 

Refrigerating  efficiency,  maximum      .             .  .      106 

Refrigerator              .             .             .             .             .  -           44 

,,             piping,   size  and  area      .              .  -45 

Regnault's  determinations  of  specific  heat            .  8 

Regulation  of  brine  temperature         .             .  -73 

,,              suction  and  discharge  valve-lift    .  37 

SALT,   and  brine  from  .             .             .             .  66  to  71 

Separator      .             .             .             .             .             .  38  to  40 

,,        for  anhydrous  ammonia  distilling  apparatus,      112 

,,          jacket-water  for               ...  53 

Specific  heat       ...                          .  .         4 

,, '          ,,  '  of  air  .....  7 

,,           ,,     ,,    ammonia           .             .  .7 

55           11     11    brine           ....  73 

• .-.,,           ,,     effect  of  temperature  and  pressure  on,         6 

,,           ,,     of  turpentine,   mercury,  and  water  .         5 

Still  for  anhydrous  ammonia         .             .             .  108 

,,  ,,  ,,         worked  under  pressure,      no 

Strength  of  brine           .             .             .             .  .69 

Stuffing-boxes           .             .             .            \             .  32 

„           .   packing  for                     .              .  .       33 

,,               lubrication  of          ...            ....  -  34 

Suction  and  discharge  valves  .              ,    -     -     .    .  .       36 

Superheating  ammonia  gas,  loss  due  to  .             .  .           58 

TEMPERATURE,  absolute          .            .  13*  16 

Tests,   calculation  results  of  24  hours      .              .  96 

,,        for  ammonia       .           .-.             .             .  .     ni- 

Testing  an  ammonia  plant  (preliminaries)           .  81  to  86 

,,  ,,  ,,       (duration  of  test)      :      .      -8^7 

Theory  of  refrigeration       ....  18 

,,                    ,,             by  compressed  air     .  .        19 


146  Tndex. 

PAGE 

Theory  of  refrigeration  by  ammonia        .  .  21 

Turpentine,  specific  heat  of    .  .  .  «j 

UNIT,  British  thermal        ....  3 

,,        of  heat,  mechanical  equivalent  of  -4 

VALVES,  expansion  ....  46 

,,  j,  regulation  of        .  •  .  73  to  75 

»         lift  37 

,,          suction  and  discharge  .  '.  -36 

Vertical  compressor  .  .  .  .  31 

Volume  of  ammonia  gas    calculated    by  compressor 

displacement       .  .       97 

,,  ,,  ,,     tables  of        .         51,  122  to  138 

,,  gases,   formulae  for  calculating  .  16 

WATER  for  compressor  jacket  .  .  52 

,,  condenser         ....  53 

,,  ,,  lessening  cost  of  -54 

,,  ,,  quantity  necessary  .  56 

,,  ,,         effect  of,  on  brine  temperature,       77 

,,  separator    .  .  .  .  -53 

Water  from  separator  of  anhydrous  ammonia  distil- 
ling apparatus     .  .  .  m 
,,       latent  heat  of    .             .             .             .             .12 
,,       specific  heat  of        ....  6 
W'orking  details  of  ammonia  plant     .              .              -47 
Worm  for  condenser           .             .             .             .              42 

YIELD  of  anhydrous  ammonia  .  .          112,  113 

ZERO,  absolute        .  .  .  16 


.»•*•   0»  TH» 

{TJIUVBRSIT 


SELDEN'S  PATENT  PACKING 


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JCousins,  R.  H.    Strength  of  beams  and  columns,  O,  5.00 

Cromwell,  J.  H.    Easy  lettering,  Q,  .50 

Cross,  C.  F.  and  Bevan,  E.  J.    Paper-making,  illus.,D  4.00 

*Cross,  Bevan,  and  King.    Report  on  fibrous  substances,  2.00 

Cullen.  W.    Construction  of  waterwheels,  plates,  O,  2.00 

*Cunningham,  D.,  Earthwork  Tables,  D,  4.25 

Cutler,  H.  A.  and  Edge,  F.  J.    Setting  out  curves,  Tt,  1.00 

Dahlstrom,  K.  P.    The  firemans  guide,  5th  ed.,  D,  .50 

Davey,  H.    Differential  expansive  pumping  engine,  O,  .80 

Davies,  F.  J.    Standard  practical  plumbing,  Q,                  ,  3.00 

Dearlove,  A.    Working  speed  of  cables.  Tt,  .80 

-  Delano,  W.  H.    Natural  Asphalt  and  Bitumen,  D,  paper,   .50 
Denning,  D.    Woodcarving  for  amateurs,  illus.,  pap.,  D,    .40 
JDenton,  J.  B.    Agricultural  drainage,  O,  paper  1.00 

* Intermittent  downward  filtration,  O,  2.00 

Diesel,  R.    Rational  Heat  Motors,  O,  2.50 

Dixon,  T.     Millwright's  guide,  6th  ed.,  D,  1.25 

Donaldson,  W.    Constructing  oblique  arches,  O,  plates,  1.50 

Solid  beams  and  girders,  0,  1.50 

Tables  for  platelayers,  plates,  D,  1.50 

Water  wheels,    O,  2.00 

Transmission  of  Power  by  fluid  pressure.  O,  2.25 

Drysdale,  J.,  and  Hayward,  J.  W.    Housebuilding,  O,  3.00 

Dubelle,  G-.  H.     Soda  fountain  drinks,  D,  2.50 
Du  Moncel,  Th.  Electro-motors,  tr.  by  C.  J.  Wharton,  D,  3.00 

*Dunbar,  J.    Practical  papermaker,  3rd  edition,  T,  1.00 

Dye,  F.    Fitting  hot-water  apparatus,  illus,  D,  1.00 

Hot  water  fitting  and  steam  cooking  apparatus,  S,  .50 

Popular  Engineering,  Q,  3.00 

*Ede,  G-.    Management  of  steel.    5th  ed.,  D,  2.00 

* Gvm  material,    S,  2.00 

Electrics,  (Practical.)    A  universal  handy-book,  I>,  .75 

;:  Eldridge,  J.    Fixing  hot-water  apparatus,  2nd  ed.,D,  p.  .40 

* Pump  fitter's  guide,  plates,  D,  paper  .40 

* The  gas  fitter's  guide,  D,  paper,  .40 

J  Engineers'  Data  book,  illus.,  pap.,  S,  1.00 

Engines  and  boilers,  How  to  run.    Illus.,  S,  1.00 

*Fahie,  A.    House  Lighting  by  Electricity,  O,  .80 

Fahie,  J.  J.    History  of  electric  telegraphy,  D,  3.00 

Fishbourne,  G-.    Stability  the  Seamen's  Safeguard,  S,  .40 

Fleming,  J.  A.    Short  lectures  to  electrical  artisans,  D,  1.50 

Fletcher,  W.    Abuse  of  the  steam  jacket,  S,  paper  1.20 

Steam  Locomotion  on  common  roads,  O,  3.00 

Foden,  J.    Boiler-maker's  companion,  D,  2.00 

*Foster,  J.  Evaporation  by  the  multiple  system,  illus.  0.  7.50 

French  polisher's  manual,  Tt,  paper.  .20 

Fullerton,  W.    Architectural  examples,  200  plates  0,  6.00 

Grillett,  W.    The  phonograph  and  how  to  construct  it,  D,  2.00 


SCIENTIFIC   BOOKS. 


Girder,  W.  J.    Weight  of  iron,  folding  card.  .40 

*Grorham,  J.    Construction  of  crystal  models,  plates,  D,    2.00 
Graham,  D.  A.    Commercial  values  of  gas  coals,  O,  3.00 

Graham,  J.C.    Steam  and  the  use  of  the  indicator,  O,       3.50 

,  M.    Construe,  and  Working  Kegerator  Furnaces,  S,  1.25 

Grant,  J.    Strength  of  cement,  O,  4.25 

G-reenwell,  G.  C.    Mine  engineering.  3rd.  ed.  64  plates  Q   6.00 
Grimshaw,  H.    Kitchen  boiler  and  water  pipes,  O,  .40 

Gripper,  C.    Tunnelling  in  heavy  ground,  O,  3.00 

Grover,  J.  W.    Estimates  etc.  for  railway  bridges,  F,      12.60 

Iron  and  timber  railway  superstructures,  F,  17.00 

Haldane,  J  .  W.  C.    Civil  and  mech.  engineering,  0,         4.50 

Steamships  and  their  machinery,  O,  6.00 

Hallatt,  G.  W.  T.     Hints  on  arch,  draughtsmanship,  T,       .60 
Halliday,  G.  Mechanical  drawing.  12  plates,  F,  2  pts.,  each  .75 
* Notes  on  design  of  small  dynamos f  O,  1.00 

Mechanical  graphics,  O,  2.00 

Belt  Driving,  O,  1.50 

II  Handy  Sketching  Book,    5in.  x  8in.,  paper,  .25 

II Pad,    lOin.  x  8in.,  paper,  .25 

JHardaway,  B.  H.    Tables  and  formulae  for  R.  R.  eng'rs.  2.00 
Hawkins,  N.    Calculations  for  engineers  and  firemen.  O,  2.50 
Heaford,  A.  S.    Strains  on  braced  iron  arches,  O,  2.40 

Heath,  A.  H.    Manual  on  lime  and  cement,  D,  2.50 

Hedges,  K.  Continental  Electric  Light  Central  Stations,  Q,  6.00 

American  Electric  Street  Railways,  Q,  5.00 

Hennell,  T.    Hydraulic  tables,  D,  1.50 

Henthorn,  J.  T.  and  Thurber,  0.  D.  The  Corliss  engine,S,  1.00 
Hering,  0.    Winding  magnets  for  dynamos,  D,  1.25 

Hett,  O.  L.  Turbine  manual  and  millright  hndbk,  O,  pap,     .80 
Hick,  J.    Leather  collars  in  hydraulic  presses,  0,  pap.        .40 
H  Higgs,  P.    Algebra  self-taught,  fourth  ed.,  D,  .60 

H.  L.    Screw  cutting  tables  for  engineers,   O,  bds.  .40 

Hodgetts,  E.  A.  B.    Liquid  fuel,  0,  2.50 

Hodgson,  F.  T.    The  Hardwood  finisher,  D,  1.00 

Holloway,  Thos.    Levelling,  O,  2.00 

Hood,  Chas.    Warming  buildings  by  hot  air,  etc.    O,         6.00 
Koskiaer,  V.    Testing  telegraph  cables,  D,  1.50 

Hoskins,  G.  G.    The  clerk  of  works,  3rd  ed.,  D,  .60 

Hospitaller,  E.    Domestic  electricity  for  amateurs,  O,       2.50 
Hornby,  J.    Gas  Engineers  Laboratory  Handbook,  D,        2.50 
Hovgaard,  G.  W,  Submarine  boats,  plates,  D,  2.00 

Hughes,  N.     Magneto  Haud  Telephone,  8,  1.00 

Hughes,  T.    English  wire  gauge,  O,  paper  1.00 

,  G.    Construction  of  the  Modern  Locomotive,  O,        3.50 

Hurst,  J.  T.    Handbook  for  arch.  Surveyors,  14th  ed.  Tt,      2.CO 

Tredgold's  elementary  principles  of  carpentry.  O,      5.00 

Hutchinson,  E.    Girder  making,  plates,  0,  4.25 


SCIENTIFIC    BOOKS. 


*Iron  and  Steel  Institute.    Journal  of  the.  Half-yearly,  O,  6.00 

* Proceedings  in  America  (special  vol.),  O,  6.00 

*Jeans,  J.  S.    Waterways  and  water  transport,  0,  5.50 

Jenkin,  F.    Report  committee  electrical  standards,  O.  3.75 

Johnson,  F.  R.    Girder  and  Roof  Trusses,  D,  2.50 

Jordan,  C.  H     Weights  of  iron  and  steel,  4th  ed.,  Tt.  1.00 

Keerayeff,  P.    Tables  of  speeds,  tr.  by  S.  Kern,  T,  paper  .20 

Kempe,  H.  R.    Handbook  of  electrical  testing,  O,  7.25 

Kent,  W.  Gr.    The  water  meter,  illus.,  D,  1.60 

Kennedy,  A.  and  Hackwood,  R.  W.    Railway  curves,  Tt,  1.00 

-  King,  W.,  and  Pope,  T.  A.     Gold,  Copper  and  Lead,  D,   4.00 
*Kirkpatrick,  T.  S.  G.    Hydraulic  Gold  Miners'  Manual,  D.  2.25 
Knight,  C.    Construction  and  manipulation  of  tools,  Q,  7.25 
Kutter,  W.  R.    Hydraulics,  tr.  by  L.  D'A.  Jackson,  O,  5.00 
La  Nicca,  J.    Turners'  and  Fitters'  pocket-book,  pap.  .20 
Lathes  and  Turning,  Examples  of  lathes.   O.  1.00 
Laxton's  Bricklayer's  tables,  Q,  2.00 

Excavators  tables,  Q,  2.00 

Leaning,  J.    Quantity  surveying,  2nd  ed.,  plates,  D,  3.50 

*Leask,  A.  R.    Triple  and  quadruple  engines,  &c.,  D,  2.00 

* Breakdowns  at  sea  and  how  to  repair  them,  D,  2.00 

:;: Refrigerating  Machinery,  D,  2.00 

Lee,  D.    Manual  for  gas  engineering  students,  S,  .40 

J  Lent,  F.  T.    Suburban  architecture,  illus.,  O,  1.00 

Lindsay,  Lord.    Screw  cutting  tables  for  engineers,  O,  .80 

Little,  Gr.  H.    Marine  transport  of  petroleum,  D,  3.50 

Livingstone,  D.    Setting  out  of  railway  curves,  D,  4.25 

Lock,  C.  Gr.  W.    Sugar  growing  and  refining.  200  illus.,  O,  10.00 

Coffee:  culture  and  commerce,  illus. ,D,  4.00 

Tobacco  growing  and  manufacturing,  illus.,  D,  3.00 

Practical  gold  mining,  illus.  O,  15.00 

Ore  dressing  machinery,    Q.  10.00 

Miner's  pocketbook,  5-00 

*Longridge,  J.  A.    The  construction  of  ordnance,  O,  10.00 

* Internal  Ballistics.  O,  7.20 

* Smokeless  powder,  O,  1.20 

* The  artillery  of  the  future,  0,  2.00 

*Love,  H.  D.    Hydraulics,  O,  2.00 

Lovibond,  T.  W.    Brewing  with  raw  grain ,  O,  2.00 

Luard,  C.  E.    Stone:  how  to  get  it  and  how  to  use  it,  O,  .80 

*Lukin,  J.    Turning  lathes,  illus.,  D,  1.00 

Macfarlane,  J.  W.    Pipe  founding,  plates,  O,  4.00 

Mackesy,  W.  H.    Table  of  barometrical  heights,  Tt,  1.25 

*Main,  T.    Progress  of  marine  engineering,  D,  3.00 

Manning,  R.    Sanitary  works  abroad,  O,  paper,  .80 

Mansergh,J.    Thirlmere  water  scheme,  maps,  O,  paper  .60 

*Marshall,  L.  C.    Practical  flax  spinner,  illus.,  O,  6.00 

Martin,  W.  A.    Screw  Cutting  Tables,  O,  .40 


SCIENTIFIC   BOOKS. 


Masters,  H.    An  architects  letter,  O,  paper,  .40 

*Matheson,  E.    Engineering  enterprise  abroad,  illtis.,  O,  7.50 

Depreciation  of  factories,  2nd  ed.,  O,  3.00 

and  Grant.    Handbook  for  engineers,  pap.,  Tt.,  .80 

Maxwell  and  Tuke.    Disposal  of  sewage,  O,  paper  .40 

Maycock,  W.  P.    Electrical  notes,  Tt,  1.25 

Merrett,  H.  S.    Surveying,  4th  ed.,  rev.  by  G.  W.  Usill.  5.00 

Middleton,  R.  E.    Measurements  at  the  Forth  bridge,  O  1.20 

Millar,  W.  J.    Principles  of  mechanics,  D  .60 

Millis,  C.  T.    Metal  plate  work,    illus.,  D,  3.50 

Molesworth,  G-.  L.    Metrical  tables,  Tt,  ..60 

* Pocket-book  for  civil  and  mech.  engineers,  Tt,  2.00 

and  Hurst,  J.  T.    Pocket-book  of  pocket-books,  Tt,  5.00 

Moritz,  E.R.,  Morris,  G-.  H.  Science  of  Brewing,  plates,  D,  T.fiO 

Murgue,  D.    Centrifugal  ventilating  machines,  tr.   O,  2.00 

Myers,  W.  B.    The  "Schwedler  bridge,"  plates,  0,  pap.  1.00 

Nares,  Capt.  Sir  G-.  S.    Seamanship,  plates,  O,  3.00 

Nelthropp,  H.  L.    Watchwork :  past  and  present,  D,  2.50 

Newman,  J.    Notes  on  concrete,  2nd  edition,  D,            .  2.50 

Newman,  J.    Earthslips  and  subsidences,  D,  3.00 

Notes  on  Cylinder  Bridge-Piers  O,  2.50 

* Scamping  Tricks.    D,  1.00 

Nissenson,  0-     India  rubber  manufacture,  D,  paper,  .75 

Treatise  on  injectors,  D,  paper,  .50 

Nystrom,  J.  W.    Steam  Engineering,  O,  1.50 

Elements  of  Mechanics,  O,  2.00 

Olander,  E.    New  method  of  graphic  statics,  F,  4.25 

Ornamental  Penman's  P'kt-bk.  of  Alphabets,  D,  paper,  '20 

JOtt,  Karl  von.    Graphic  statics.    Tr.  by  G.  S.  Clarke,  D,  1.50 

*Paterson,  M.  M.  Testing  pipes  and  pipe-joints,  O,  pap.,  .80 

Penman,  W     Land  surveying,  O,  3.50 

Phillips,  J.    Drainage  of  towns,  O,  paper  .60 

Phin,  J.    Trade  secrets.  D,  .60 

Porter,  C.  T.    Richards  Steam  engine  indicator.  O,  3.00 

Practical  Electrics.    Illustrated,  D.  .75 

Pray,  T.  J.    Twenty  years  with  the  indicator.  O.  2.50 

Steam  tables  and  engine  constants,  O,  2.00 

Price,  W.    Turners'  handbook  on  screw-cutting.    S.  .40 
*Proc.  Munic.  and  Sanitary  engineers  and  surveyors, 

edited  by  Thos.  Cole.    Published  annually. 

Rapier,  R.  C.    Remun.  railways  for  new  countries,  Q,  6.00 

Redwood,  I.  I.    Practical  Ammonia  Refrigeration,  S,  1.00 

*Reed's  Engineers'  h'nd'k,  by  W.  H.  Thorn.  13th  ed.,  O,  4.50 

* examination  papers,  by  W.  H.  Thorn,  2nd.  ed.,  O,  2.00 

Reeves,  R.  H.    Bad  drains  and  how  to  test  them,  D,  1.40 
Reid,  H.    Manufacture  of  portland  cement,  plates,  O, 

Reis,  P.    Inventor  of  the  telephone,  by  S.  P.  Thompson.  3.00 

Reynier,  E.    Voltaic  accumulator,  Tr,  O,  3.00 


SCIENTIFIC    BOOKS. 


R'>hards,  W.    Gas  consumer's  handy  book,  S,  paper  .20 

Manufacture  of  coal  gas,  plates,  Q,  12.00 

*Richards,  J.    Operation  of  woodworking  factories,  D,  1.50 

Workshop  manipulation,  D,  1.00 

Centrifugal  Pumps,  O,  1.00 

Rigg,  A.    Treatise  on  the  steam  engine,  plates,  Q,  10.00 
*Rigg,  A.  and  G-arvie,  J.     Modern  guns  and  smokeless 

powder,  O,  2.00 
Ritter,  Prof.    Iron  roof  and  bridge  construction,  tr.  by 

H.  R.  Sankey,  O,  6.00 

-  Roberts,    Charles   W.     Practical  Advice  for  Marine 

Engineers,  S,  1.00 

Robertson,  F.    Engineering  notes,  O,  6.00 

Robinson,  H.    Sewage  disposal,  2nd  ed.,  D,  2.00 

Gas  and  petroleum  engines,  6.50 

*Robinson,  H.  Systems  of  distributing  electricity,  O,pap,   .80 

Rowan,  T.    Disease  and  putrescent  air,  O, paper  .80 

Spontaneous  combustion  of  coal,    O,  2.00 

Rowell,  H.    Manual  of  hard  soldering,  D,  .75 

Salis,  R.  de     Hydraulic  tables  for  circular  sewers,  0,  p.  .40 

Salwey,  E.  R.    Light  railways.  0,  2.00 
Sang,  E.    Lessons  in  applied  science.    3  pts,  D,        each  1.25 

•'"Saunders,  C.  A.    Handbook  of  Practical  Mechanics,  S,  1.00 
Scamell,  G-.    Breweries  and  malting.     Second  edition, 

by  F.  Colyer,  plates,  O,  5.00 

*Screws  and  Screw  Making.    D,  1.2g 

Sexton,  M.  J.    Pocket-book  for  boiler-makers,  2nd  ed.  2.00 

Shaw,  E.  M.    Fires  in  theatres,  new  edition  D.  1.25 

Simmonds,  F.  L.    Useful  animals  and  their  products,  S,  .80 

Animal  food  resources  of  different  nation  j,  D,  1.00 

Hops:  cultivation,  commerce,  and  uses,  D,  1.25 

Tropical  Agriculture,  0,  8.00 

Smeaton,  J.    Plumbing,  drainage,  hot  water  fitting,  D,  3.00 

*Society  of  Engineers  transactions  for  1890,    u,  6.00 

Spang,  H.  W    Lightning  protection,  D,  .75 

Spencer,  A.    Roll  turning,  56  large  folding  plates,  0,  8.00 

-    Appendix  to  Roll  turning,  22  folding  plates,  O,  4.25 

Ditto,  complete  in  2  vols.,  78  plates,  O,  12.00 

Spons'  Dictionary  of  Engineering.  In  8  divs.  cloth  $5.00 

each;  3  vols.  cloth  $40.00;  3  vols.  half  morocco  50.00 

ditto    Supplement.    In  3  divs.  cloth  $5.00  each;  in 

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Spon,  E.  "Sinking  and  boring  wells,  2nd  ed.,  D,  3.50 

Spons'  Encyclopaedia,  5  v.  cloth  $27,  2  v.  half  morocco  35.00 

Mechanics'  own  book,  illus.,  O,  2.50 

Tables  and  memoranda  for  engineers,  Ss,  (in  case)     .60 

Spretson,R.E.    Casting  and  founding,  5th  ed.,  plates,  O,  6.00 
Sprague,  J.  T.  Electricity,  theory  and  practice,  3rd  ed,  D.  6.00 

Standage,  H.  0.    Polish  and  varnish  maker,  D,  2.50 


SCIENTIFIC    BOOKS. 


*Stanley,  W.  F.    Motions  of  fluids,  illus,  0,  6.00 

* Mathematical  drawing  instruments,  illus.,  D,  2.00 

* Surveying  and  Levelling  Instruments.  D,  3.00 

Steel,  J.    Malting  and   brewing,  plates,  O,  2  vols,  7.50 

Stephens,  V.     Wrinkles  in  electric  lighting,  D,  1.00 

Stone,  T.  W.    Simple  hydraulic  formulae,  D,  1.50 

* Water  supply  in  new  countries,  D,  2.00 

Stoney,  B.  B.  Strength  and  proportion  of  riveted  joints,  0,  2.00 

Streatfaild,  F.  W.    Organic  chemistry.  D,  1.26 

$  Stuart,  D.  M.  D.    Coal  Dust  an  Explosive  Agent,  Q,  3.00 

Symons,  G-.  J.    Lightning  rod  conference,  O,  3.00 

Terry,  Gt.    Pigments,  paint  and  painting,  illus.,  D.  3.00 

*Thompson,  S.  P.    Electricity  in  mining,  paper,  O,  .80 

Electrical  tables  and  memoranda,  Ss,  .50 

* Murcurial  air-pump,  illus.,  O,  paper,  .60 

The  electromagnet,  0,  6.00 

Turner,  J.  H.  T.  and  Brightmore,  A.  W.    Waterworks 

Engineering,  10.00 

Turning.    Geometrical  turning  simplified,  O,  1.23 

Examples  of  lathes,  apparatus  and  work,  O,  1.00 

Unwin,  W.  C.    Short  logarithmic  tables,  O,  1.40 

*Uppenborn,  F.    History  of  the  transformer.  D,  paper.  -75 

*Useful  Hints  to  sea-going  engineers,  D,  1.40 

Vosmaer,  A.    Iron  and  steel,  D,  2.50 

-  Walker,  S.  F.  Electric  lighting  for  marine  engineers  D,  2.00 
Walmisley,  A.  T.    Iron  roofs,  2nd  ed,  plates,  Q,  hf.  mor.  21.-."0 
Walsh,  M.    Brickmaking  in  Western  India,  O,  paper,  .40 
Watson,  E.  P.    How  to  run  engines  and  boilers,  S.  1.00 
Welch,  E.J.C.    Designing  belt  gearing,  S,  paper,  .20 

I Designing  slide  valve  gearing,  D,  1.50 

Wheeler,  W.  H.    Drainage  of  low  lands,  plates,  O,  4.00 

Canals.    O,  paper,  .40 

Willcocks,  W.    Egyptian  irrigation.  Illus.  0,  15.00 

Wood  W.  H.    Stairbuiluing  and  Haudrailing,  Q,  4.25 

Woodward,  C.  J.    Five  Figure  Logarithms,  S.  1.60 
Workshop  Receipts.    Mechanical,  chemical,  electrical, 

and  metallurgical,  five  volumes,  each  2.00 

Wurtele,  A.  S.  C.    Standard  measures,  O,  .50 

*Wylie,  C.    Treatise  on  iron  founding,  illus.,  D,  2.00 

Young,  W.  Municipal  Buildings  Glasgow.    F.  4.25 

Town  and  country  mansions,    plates,  Q,  12.50 

Zeuner,  Dr.  G-.    Valve-gear,  tr.  by  Prof.  J.  F.  Klein,  O,  5.00 


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